ThunderCats Episode Rating Graph

Hatchiman rescues an old woman not knowing it's Luna. She "invites" him to her "cave" and there she and Chilla and Aluro attack him and take his sword, the Thundercutter. The Thunderkittens find Hatchiman and rescue him. The Lunataks plan to use the Thundercutter with their new samurai robot, Automaton, to fight Lion-O and the Sword of Omens. The Thundercutter can't tell who's good and who's evil in the fight but when Hatchiman touches the sword, the Thundercutter destroys the robot.

After overhearing Snarf telling the Thunderkittens and Pumyra a story about Mumm-Rana's magic belt and Queen Luna (Luna's grandmother), Luna and Amuk journey to the white pyramid and take Mumm-Rana's belt, destroying her pyramid in the process. Pumyra tries to stop her but she gets sealed up in the pyramid. Amuk becomes jealous when Luna no longer needs him and during his ""little temper"", he accidently frees Pumyra. Then Luna forces Slithe and Monkian to help her ambush Lion-O and Panthro. During the battle with ""Princess"" Luna, Lion-O uses the sword to restore Mumm-Rana and she retakes the belt and defeats Luna. Amuk later arrives and destroys the belt.

The Thundercats use a new Tower signal to guide a Thunderian ship in; aboard are Baron Tass and Mr. Grubber, a devious pair of Thunderians. Later Lion-O sends Torr, Baron Tass and Mr. Grubber to get water, but on the way the Baron stops at the Well of Doubt and gets some of its water. The water causes a person to become very doubtful of his own abilities. When they get back to the Thundercats, Baron Tass gives some of the water to Lion-O. On the way to inspecting the new Tower in the Whisker, Lion-O feels the effects of the water and causes the Whisker to crash. Tass comes back (from getting his Guardsman, giant stone-men), and has them attack the Thundercats. Jagara has the others hold the Sword, and when Lion-O grabs hold of the sword, he's free of the water's effect. Then he fights off the Guardsman, and makes a storm, which causes the Guardsman to fall apart, and Tass promises to change his ways.

New Thundera is being torn apart and the Thundercats must present certain artifacts at various dangerous locations that used to be beautiful places, then Lion-O must go into the book and give the Key of Thundera to the guardian of the book ""at the 24th hour,"" or the Thundercats will be frozen in time and New Thundera will be destroyed. But Mumm-Ra steals the book and key and journeys into the book himself. He wants to save New Thundera BUT wants the Thundercats frozen in time. The Ancient Spirits of Evil try to stop Mumm-Ra because they fear if Mumm-Ra goes into the book, their powers will cease to exist. The other Thundercats run into problems also at the locations they are supposed to be at. Lion-O goes into the book using the Sword of Omens and battles Mumm-Ra one on one, neither of them using any magic. Even when Mumm-Ra cheats, Lion-O still wins. The ASOE summon their ""champion,"" Pyron, to then fight Lion-O, but Lion-O gets the dragons in the book to fry him... He presents the key

Vultureman escapes from exile by hijacking a bookmobile. He finds a disk containing ancient history about two powerful evil forces on Third Earth: Mumm-Ra and his enemy Zaxx. Zaxx used a Rosencrest medallion, but Zaxx was defeated when Mumm-Ra stole the medalion trapping Zaxx in it. Vultureman plots to get the medalion, defeat Mumm-Ra, and rule the universe. So Zaxx uses Vultureman to find and defeat Mumm-Ra. But there's a terrible ""side effect"" to the medalion, anyone who wears it loses his own life and BECOMES Zaxx. When Vultureman learns of this, he changes his mind. The Thundercats get caught in this situation when Vultureman attacks Panthro and Snarf and after they crash, Snarf dissappears. Zaxx then uses Snarf to attack Mumm-Ra and Zaxx takes over Snarf's body. The other Thundercats arrive and save Snarf. Mumm-Ra defeats Zaxx once more by takin the medalion, but the pyramid also collapses on Mumm-Ra.

Willa is captured by the Mutants, and Tygra and Nayda, Willa's sister, must go to Castle Plun-darr to save her. Tygra uses the invisibilty power of his whip on both of them, so they could sneak into the castle and rescue Willa, but having 2 people at a time takes too much power from the whip, so they are stuck being invisible. Lion-o uses the Sword to make them visible once again and Willa is rescued.

While trying to figure out a way to read the Book of Omens, Lion-O tries looking through the sword at the book. He is immediately drawn into the book, where a voice asks him if he has ""the key."" Lion-O says he doesn't, and four dragon heads appear and shoot fire at him. Snarf, who saw Lion-O get sucked into the book, tries to show Cheetara what happened, and he too gets sucked in. Mumm-Ra, who also watched Lion-O get sucked in, goes to cats lair and takes the book so he can destroy it with Lion-O inside. Meanwhile, just by coincidence, Panthro finds an odd looking key on Thundera. He and Tygra head back to Third Earth with the key, not knowing what it's for. Back on Third Earth, Mumm-Ra is just about to boil the book when Lion-O calls for the sword, and it brings him and Snarf back outside. Mumm-Ra takes the sword and looks through it at the book, and he gets sucked in! But Lion-O has to save him because of the code of Thundera, and Lion-O does save him. Panthro and Tygra arrive with t

Panthro, Tygra, and Cheetara return to New Thundera in the Feliner to find more of the Treasure of Thundera, but Mumm-Ra shoots the Feliner down and, as the Fog of Despair, sends them to the Canyons of Youth, which changes them back into Thundercubs. Then Mumm-Ra disguises himself as Lion-O and tells the Thundercubs to find the treasure for him. Meanwhile, back on Third Earth, Lion-O and Snarf decide to go rescue the Thundercats on New Thundera, but they must ask the Mutants to take them to New Thundera in the Rat-Star. The Mutants agree, secretly planning to attack Lion-O once they're in space. They do attack and imprison him and Snarf on the way to Thundera, but they manage to break out. Cheetara meanwhile, using her sixth sense, locates part of the treasure, the Mirror of Truth. The real Lion-O shows up, and uses the Sword of Omens with the Mirror of Truth to restore the cubs to their proper age, and Mumm-Ra reveals himself and turns into Mumm-Ra the everliving. Cheetara uses the mi

Mumm-ra transforms himself into a ro-bear berbil (a Thundercat ally). He acts hurt and the Thundercats let him stay at Cats Lair. One night, Mumm-ra(the berbil) puts all the Thundercats under his spell, except Snarf, because Tygra held off Mumm-ra just long enough for Snarf to escape. Lion-O was sleeping out in the woods, and Snarf ran to him and told him what happened. Lion-O came back and fought Mumm-ra, who was actually beating Lion-O. Mumm-ra was wearing special glasses so he couldn't see his reflection. Eventually, Lion-O used the Thundercat signal, broke Mumm-ra's spell and his glasses, and finally defeated him with his reflection.

Mumm-Ra orders Amortus, a being he banished to the Land of No Return centuries ago, to destroy Lynx-O. Amortus makes Lynx-O crash in the Thunderstrike, and then he touches Lynx-O's face. The spell from the touch makes Lynx-O feel like he is an outcast, so he leaves to join Amortus in the Land of No Return. The other TCats, Lion-O, Panthro, and Cheetara, go after him. In the Land of No Return, Amortus again touches Lynx-O, this time causing him to turn to stone. The other TCats arrive and try to beat Amortus, but he touches all of them, causing them to start turning to stone. But just as Lion-O is about to turn entirely to stone, he calls the Sword and it breaks them free. It also releases other warriors trapped by Amortus, and they all come and defeat him. Lynx-O is rescued just in time- just before the stone is permanent- and they all go home

An evil robot monster is attacking the Tuska Village, in an area unexplored by the Thundercats. Turmagar, the leader of the Tuskas, travels to the Cat's Lair to ask for aid in defeating the Techno-Pede robot which is destroying his village. The Thundercats agree to help Turmagar, and set out to the Tuska Village.

The Ancient spirits of evil show Mumm-Ra the story of King Arthur, and explain to him that the strongest sword that ever existed was Excalibur, Arthur's weapon. Mumm-Ra disguises himself as Arthur, and returns to lake where the sword is guarded by the lady of the lake. Fooled by his disguise, the lady gives Mumm-Ra Excalibur. The disguised Mumm-Ra challenges Lion-O to a dual, and Lion-O foolishly accepts the challenge. The sword clash, and Excalibur is victorious. The eye of Thundera is split in two, and the Thundercats become powerless. Merlin, Arthur's teacher and a famous magician stops Mumm-Ra from destroying the Thundercats, and restores the eye to its original state.

The Thunderkittens steal the Thundercats' weapons so they can prove they can use them, but the Mutants steal the weapons! Lion-O and the kittens must get the weapons back from the Mutants.

The scene changes to Hook Mountain, where Lion-O must beat Tygra at a test of mind power. The Tiger Clan on Thundera were given special mind powers that enable them to produce illusions to their enemies. Lion-O must be able to distinctly separate the real from the unreal. Lion-O is clever enough to see past Tygra's illusions, and is able to earn his Thundercat insignia during day four of his trials.

Wily Kit and Kat stand in Lion-O's way on the third day of his trials. Lion-O must beat them through the maze of infinity. Attempting to stop Lion-O and slow him down, the kids set traps in the maze. He manages however to avoid their traps. In order to beat them through the maze, Lion-O plays their own tricks on them, and tricks them into losing the race through the maze.

An old iceburg on Hook Mountain begins to melt, and encased in it is an ancient being known as the Ice King. He begins to destory Snow-Man's caslte at the top of Hook Mountain, and frezzes Snow man in solid ice. Snow-Meow, his faithful compainion seeks out Lion-O to do away with the being and save his master. Lion-O fails, and is also frozen. Once again Snow-Meow sets out to find the other Thundercats. They arrive only to face defeat, and Cheetarah is the only one to survive. She uses the sword to restore Lion-O to normal, and he in turn restores everyone else. They discover that the Ice King is looking for an ancient egg to see his wife, the Queen one last time before he dies. They understand his madness and assist him in finding the egg

While burying one of the time capsules that transported the Thundercats to Third Earth, it smashes apart and Lion-O gets caught in its gases, making him younger and younger by the minute. The other Thundercats must find a way to reverse the process and realize the Cave of Time is the only way, but they must get Lion-O there before he "vanishes" from existence. Things get worse when the young Lion-O and Snarf are captured by the Lunataks.

The normally submissive JackalMan decides to start his own army in hopes of conquering Third Earth by himself. He does manage to give the Thundercats trouble, but soon he is defeated and ends up crawling back to the other mutants at Castle Plundarr, who weren't very happy that he rebelled in the first place.

Mumm-Ra awakens the Rock Giant, an ancient monster made of stone which looked like a mountain to the TCats. When it wakes up, Mumm-Ra sends it to destroy Cats Lair. The TCats try and defeat it using the Thundertank, and eventually with the help of the Sword, the giant is beaten.

After another earthquake caused by Mumm-Ra ruins the new Cats Lair construction site, the Thundercats go to see Jaguara and confront Mumm-Ra. Unfortunately, Mumm-Ra puts up a force field over entrance. Jaga appears to Lion-O and tells him to use the Eye of Thundera to get to Jaguara and the Gyroscope. Lion-O does so and battles Mumm-Ra, who throws him into the bottomless pit underneath the Gyroscope. Lion-O however, manages to throw his grappling hook to the top, which pulls him back up. Lion-O then shines the signal, which goes through the force field. All the Thundercats leap through the signal which takes them through the force field. Together, they fire all their weapons at Mumm-Ra and he is defeated. But before he leaves, he breaks the cord that holds the Gyroscope above the pit and it falls through. Now, New Thundera is literally falling apart. But Lion-O throws the sword in the spot where the Gyroscope used to be and calls upon the Thundercat Ancestors for help. The sword starts

Mumm-Ra pretending to be one of the ThunderCats friends takes Lion-O to a gallery of the ThunderCats accomplishments. However, the pictures can come to life and Lion-O must battle Rataro, Safari Joe, and others. ONce the other ThunderCats arrive they end up in trouble and Lion-O is confronted by Mumm-Ra who has made himself into a carbon copy of Lion-O. It's Lion-O VS Lion-O and is a draw, until Lion-O shows Mumm-Ra his reflection.

Wily Kit and Kat are constructing a well for the New Cat's Lair on New Thundera. The Thundercats on New Thundera receive a distress signal from Thunderian refugees trying to find their way to New Thundera. The Kittens are left alone with Snarf on at the New Cat's Lair, and Lion-O and Snarfer are out constructing an early warning device (I guess for weather purposes). The rest of the Thundercats seek out the refugees in space. When Wily Kit and Kat strike water, they accidentally unleash a monster that Jaga trapped in the underground lake centuries ago. Frogman, with aquatic powers, tries to sink the New Cats Lair. Lion-O however re-traps Frogman in his watery prison.

Mumm-Ra sends Ma-Mutt disguised as Mandora to free the Mutants from Capt. Bragg's circus train and sends Bragg and Crowman falling into deep space. The Mutants are then ordered by Mumm-Ra to get rid of Tygra and Pumyra. The Mutants attack Snowman on Hook Mt. and Snowmeyow gets Pumyra for help and Tygra contacts the real Mandora to save Bragg and Crowman. Then together, they recapture the Mutants. Meanwhile on New Thundera, the earthquake tremors grow worse and the new Cats Lair collapses trapping Snarf in the ruins. Lion-O uses the sword to contact the other Thundercats and they rush to the Lair to save Snarf. Afterwards, Mumm-Ra destroys the Gyroscope's regulator...

Lion-O, Panthro, and Snarf set out to look for more pieces of the Treasure of Thundera, and Mumm-Ra sets a trap for them. He freezes them in the caverns of cold on Thundera. Meanwhile, back on third earth, the Luna-tacs, in need of another source of power for their ship, use exercise machines to power it up. They capture the other Thundercats and force them to workout on the machines to power up the ship. The Thundercats manage to overwork the power supply, and escape from Sky Tomb. Back in the caverns, Snarf manages to get the sword of omens to Lion-O with his tail, and they escape and return to third earth.

A spaceship approaches third Earth and it sets off all the alarms of the ThunderCats, Mutants and even Mumm-Ra. It contains enough radioactive material to put an end to the ThunderCats. Jackelman takes the recovered materials first and Mumm-Ra takes it from him. The ThunderCats battle Mumm-Ra on top of the Dark Pyramid for the sphere and eventually win, setting the materials to explode safely in space.

Lion-O encounters two beings who each tell him the other's race is evil and cannot be trusted. Unfortunately, he makes the mistake of assuming that the more attractive of the two is the one he should side with.

Lion-O loses the Sword of Omens in an avalanche. Panthro battles the Fist-Pounder with the ThunderTank. The Mutants arrive at Fire Rock Mountain to take control of the prisoners.

The Ancient Spirits of Evil bring the Mirror Wraith to Mumm-Ra, and he disguises it as a child's toy. Mumm-Ra then intercepts a thunderian escape pod which carries in it a little girl. He gives the toy to the child (Leah), and leaves. She is rescued by the Thundercats, and goes into New Cat's Lair with the doll. The doll turns into the Mirror Wraith when left alone, and begins to destroy Cat's Lair, and the Thundercats have no clue where the evil Mirror Wraith came from.

From the Shadow Realm, the Shadowmaster contacts the Ancient Spirits of Evil (ASOE), telling them of how he captured Lion-O's father, Claudus, just before Thundera blew up. Then the Shadowmaster, through a bad dream, shows Lion-O his captured father and challenges Lion-O to a fight. Lion-O goes to the Shadow Realm through the Book and Sword of Omens, and is able to fight the Shadowmaster as long as the Sword stays bonded to the book. However, the Shadowmaster sends a huge bat to steal the Sword. It succeeds, and then Lion-O becomes very weak in the Shadow Realm. Mumm-Ra meanwhile, feeling like the ASOE will turn against him in favor of the Shadowmaster, sends Ma-Mutt to secretly steal the sword from the bat and put it back near the book. This renews Lion-O's strength, who calls for the Sword, rescues Claudus, and exiles the Shadowmaster. Claudus leaves Lion-O, but at the end you see him and Jaga standing next to each other in that blue, ghostly form. Now Lion-O has 2 mentors to give hi

A bounty hunter known as Captain Bragg comes to Third Earth to help the Thundercats get rid of the Mutants and the Lunatacks. Capt Bragg tricks Wilykat in going with him and they first go after the Mutants. After capturing them, they go to capture the Lunataks. They capture all except Luna and Amuk, who free the other Lunataks, put Bragg in a cage and tie Wilykat to the train's engine. Lion-O and Wilykit arrive to save Wilykat and the Lunataks are defeated. All the Mutants and all the Lunataks are captured and exiled.

Lion-O takes up mountain climbing, but during one of his climbs, The Mutants attack him with a thundrainium gun, Liono calls the other Thundercats, but an avalanche traps Panthro, Tygra, Slithe and Monkian, in a cave causing a limited air supply. Meanwhile Jackleman steals the sword, but Lion-O manages to get it back and saves everyone.

Hatchiman rescues an old woman not knowing it's Luna. She "invites" him to her "cave" and there she and Chilla and Aluro attack him and take his sword, the Thundercutter. The Thunderkittens find Hatchiman and rescue him. The Lunataks plan to use the Thundercutter with their new samurai robot, Automaton, to fight Lion-O and the Sword of Omens. The Thundercutter can't tell who's good and who's evil in the fight but when Hatchiman touches the sword, the Thundercutter destroys the robot.

A convergence of the Moons of Plun-Darr causes a drought on Thundera. Panthro and Snarf go looking for water, then Ezuka, the flying Serpent of Dreary Canal wanting to get water itself, attacks Panthro and Snarf and causes them to fall into the Swamp of the Laughing Lilypads, making them laugh out of control. Ezuka attacks the Lair, still looking for water. Lion-O uses the Sword to make some rain, then he and Ben-Gali use the Thunderstrike to melt some ice, but Mumm-Ra comes along and causes a flood. Lion-O calls for the others, which also free Panthro and Snarf from the laughter and they use some of the Swamps water to cause Mumm-Ra to laugh uncontrolably, and he falls in the flood waters and is washed away.

Mumm-Ra learns about the Treasure of Thundera and the Sword of Plundarr (Jaga had beaten Ratilla, who owned the Sword, and then buried the sword deep underground), and he and Ma-Mutt ""travel back in time and space"" to explore the debris of Thundera and look for the sword, which causes the planet to reform. The Thundercats find out about this and must make the journey to New Thundera to stop Mumm-Ra. Lynx-O and the Thunderkittens are left at the tower while the other Thundercats at the Lair are preparing the Feliner for the trip to New Thundera. Vultureman notices that the tower is only guarded by 3 Thundercats and goes to Sky Tomb and tells Luna. Luna then sends Red Eye and Tug Mug to attack the Tower, and they capture Lynx-O and the Thunderkittens.

Mumm-Ra summons the Berserkers and coats their armor with Thundrainium and sends them to attack the Thundercats at the Tower of Omens. Realizing that their armor is coated with Thundrainium, the Thundercats at the tower need help and Lion-O and Tygra rescue them. They create a windstorm to rub off the Thundrainium and the Berserkers retreat. Meanwhile the Lunataks invade Cats' Lair and the Thundercats must rush back to save the Thunderkittens and Snarf who are being held as the Lunataks' slaves.

Lion-O, Lynx-O, Snarf and Tygra go to the Crystal Canyon, thinking the Lunataks somehow got the Treasure of Thundera. While there, they encounter Aluro and Chilla. The two Lunataks trick the Thundercats by confusing them using with their reflections. They knock out the Thunderstrike and cause it to crash. Lynx-O is seriously injured and Lion-O is knocked unconscious. Tygra and Snarf find the Keystone and when Tygra holds the Keystone, he becomes convinced that it is making him more powerful. He uses it to restore the Thunderstrike, and heal Lion-O and Lynx-O. They return to the Lair and the other 3 Thundercats learn Tygra has become seriously addicted to the Keystone. When they try to tell Tygra he's become a slave to the Keystone, he doesn't believe them. Later in a battle against Aluro, Tygra thinks he's invincible, but Aluro proves him wrong and takes the Keystone from Tygra. Then Aluro himself becomes addicted to the Keystone. Aluro captures Lion-O and Lynx-O forcing them to come w

Vulture Man creates a device that shifts minds and bodies. He gives Panthro Snarf's body, and gives Snarf Panthro's Body. He also shifts Lion-O and Wiley-Kat, and thus makes the sword of omens unusable. Eventually, Vulture Man shoots the sword, and it causes a reaction that restores all the Thundercats to their rightful bodies.

Vultureman invents a voice imitator which can imitate ANYONES voice. The mutants use the invention to trick the Thundercats into falling for false distress calls. They go on the communication frequency that the Thundercats use and pretend to be Thundercats in danger. Each Thundercat is lured into a different danger zone of third earth. Wily Kit and Kat get trapped in the Vortex, Cheetara in a giant bee hive, Tygra in Mole-masters hole, and Panthro gets captured by the mutants. Liono and Snarf go off to save them once again, and put the mutant scheme to an end.

Finally, to prove that Lion-O is worthy to be the Lord of the Thundercats, he must defeat his worst enemy. Mumm-Ra. He manages to find a way into Mumm-Ra's tomb, and defeats him by throwing his coffin into the evil cauldrum. This is the first time that Lion-O really defeats Mumm-Ra.

Nearly all the Thundercats have been captured by the Mutants and imprisoned in Mumm-Ra's Pyramid, forcing Snarf to use his own talents to free them.

Wilykit and Kat accidentally free an ancient monster that was banished to an old shrine centuries ago. The evil monster, Mongor, begins to destroy the planet, and is much stronger than the Thundercats. He captures all the elder Thundercats with his powers. Wilykit and Kat return to the shrine to find a way to destroy him. They report back to Lion-O and tell him that in order to destroy Mongor, he has to fight the monster without looking at it. Lion-O defeats the monster and all is returned to normal.

Mumm-Ra creates device that can make Panthro clones. He embeds the spirit of Hammerhand into his clone and sets it free to destroy Third Earth. The Third Earth inhabitants blame the Thundercats for the terror because they think its the real Panthro destroying their villages and burning their crops. The real Panthro finally encounters his clone and, with the help of Lion-O, manages to destroy it. Enraged about his defeat, Hammerhand destroys Mumm-Ra's cloning device.

Mumm-Ra finds out that the Kingdom of Webs has a new Queen, Spidera. Mumm-Ra thinks he can lure Lion-O into her lair. He transforms into a diamond fairy and casts a spell on Lion-O. Snarf follows them and gets trapped in the Kingdom of Webs. Lion-O tries to save him but ends up having to call the other Thundercats. Eventually they confront and beat Spidera.

After looking at the Book of Omens, and seeing a picture of a necklace, Lion-O discovers that there are pictures of the Thundercats on the necklace. Jaga appears to Lion-O and tells him that he is looking at a picture of the Chain of Loyalty. Jaga tells Lion-O that if the chain gets broken, it would cause the Thundercats to turn against each other. In hearing this, Lion-O and the Thundercats (Panthro, Tygra, Cheetara, and the Thunderkittens) set off to Thundera to find the chain. Mumm-ra, eavesdropping on Lion-O through his pool at the pyramid, goes to Thundera, kidnaps and disguises himself as Snarf. When the Thundercats arrive, they split up into groups to find the chain, and Mumm-Ra goes with Lion-O and the Thunderkittens. Lion-O's group finds the chain and Mumm-Ra gets it, breaks it, and returns to his true form. For a while, the Thundercats, except Lion-O, fight against each other until Lion-O uses the sword of Omens, which magically puts the necklace back together. Mumm-ra is def

Wilykit and Wilykat try to stop a band of living gargoyles from robbing a Wollo but fail to do so and trail the gargoyles to a nearby Tower. Wilykat is trying force the door open when he suddenly disappears, leaving Wilykit - who was looking for another way in - close to panic. She and Lion-O (alerted by the Sword of Omens) must now brave the Tower's potentially lethal traps in order to rescue Wilykat.

When a meteorite made of pure Thundrillium crashes on Hook Mountain, the Thundercats decide to use it to replenish their depleted energy supply. But Lion-O must first gain the trust of the fierce Snowman.

Mumm-Ra and the Mutants plot to open the Time Warp Prison and release the evil Princess Ta-She in order to use her deadly Doomgaze against the Thundercats.

Lion-O and Snarf stumble upon a portable jail cell, and mistakenly open it up. Three of the galaxy's worst villains escape. One of them, a slick thief, manages to steal Lion-O's sword. Lion-O helps Mandora, the inter-stellar police officer that imprisoned the villains, recapture them, and return them to their cells.

The Mutants, once again searching for a way to destroy the Thundercats, recover some more items from their spaceship. They take their ship's engine and convert it into a giant fireball-shooting machine. The mutants terrorize Third Earth with their fireballs, until the Thundercats go to castle Plunn-Darr and destroy their dangerous new weapon.

An alien spaceship crash lands on third earth, and it can somehow communicate with Cheetara through her sixth sense. She becomes a part of the spacecraft, and begins to feel what it feels. The Mutants recover the space ship, and begin tampering with it. Little do they know that it is not only affecting the spaceship, but it is affecting Cheetara. In order to save Cheetara, the Thundercats set out to recover the space ship from the Mutants and fix it.

The Thundercats think that Snarf is getting too old, and that he is not up to doing as much as he does. To prove them wrong, Snarf saves the Thundercats from another mess. The evil Crystal Queen, Tartara, captures the Arrietta bird, whose songs enchant the Berbils' harvests. Lion-O, upset with her selfishness, goes off to save the bird, but gets caught and put under an evil spell. Snarf, managing to slip through the crystal queens defenses, saves Lion-O and frees the Arrietta bird.

Mumm-Ra has a new device, the Babylonian Barbarian Boiler, that he plans to use on Cats Lair. Ma-Mutt fools around too much and Mumm-Ra banishes him from the Pyramid. Later, the Thunderkittens, Snarf, and Snarfer bring Ma-Mutt back to Cats Lair and then Mumm-Ra fires the Boiler's beam at the Lair, which causes it to start melting. Snarfer makes a communicating device (because Ma-Mutt was trying to tell them about the beam), so they can understand Ma-Mutt. Ma-Mutt starts telling them of the Boiler, but Mumm-Ra sees this and through the Cauldron's magic brings Ma-Mutt back to the Pyramid. Then the ThunderCats construct a giant Light-Shield and use it to protect the Lair, but Mumm-Ra just boosts the power on the Boiler, destroying the Shield. Lion-O uses the Cat Signal to push back the beam, which causes the Boiler to explode, and the Signal restores Cats Lair. Mumm-Ra, who was lonely without Ma-Mutt, welcomes his dog back to the pyramid

The Thundercats briefly show Lion-O how the time capsule they recovered from the caveman works. Curious to see more, Lion-O activates it during his night-time watch, and gets caught in its projection rays. The rays send him back in time to Thundera, just before the final tremor that destroyed the planet. Meanwhile, the Mutants have built an evil robot monster that is destroying Cats' Lair. Back on Thundera, Lion-O encounters his father, Claudus, and saves him from a Mutant attack. In return, Claudus gives Lion-O the plans to the robot that was attacking the Thundercats in his own time.

Wilykit and Kat find an ancient harp that has a genie in it. His name is Charr-Nin. Mumm-Ra appears to the genie and tells him that if he destroys the Thundercats, he will be freed from his eternal prison in the harp. Foolishly, Char-Nin agrees, and begins trapping the Thundercats in his harp one by one. Mumm-Ra's plan works, and he betrays Charr-Nin. During their arguing, the Thundercats manage to escape, leaving Mumm-Ra and Charr-Nin battling beneath the earth

Mumm-Ra retrieves the Sword of Plundarr and the Thundercats arrive on New Thundera. While the Thundercats want to get the Sword and treasure, Snarf and Snarfer want to free their fellow snarfs. While the Thundercats sleep, Snarf and Snarfer sneak away, but are discovered and captured by Mumm-Ra. He disguises himself as Snarfer and he leads the Thundercats to where the treasure is located, but it can only be freed by the Sword of Omens. Once the treasure is freed, Mumm-Ra reveals himself and defeats the Thundercats with the Sword of Plundarr. Now Mumm-Ra possesses the Sword of Plundarr and the Treasure of Thundera

While investigating an earthquake, Tygra stumbles across the Garden of Delights and meets a talking plant named Silky, who offers him her fruit. But it turns out that "Silky" is another of Mumm-Ra's disguises and eating the fruit seems to have affected Tygra's mind.

An evil hunter lands on third earth in search of prey to hunt. His holographic machine can tell him about all of the Thundercats, including their strengths and weaknesses, and he is able to hunt down each one of them and put them in Thundrainium cells. He captures all of them but Lion-O and Snarf. Jaga warns Lion-O about Safari Joe before he sets out to save his comrades, and Lion-O is able to defeat him and release his friends.

Aluro invents a ""booster"" potion in hopes that it can make Sky Tomb able to fly to Thundera. It doesn't work, and he throws the potion into the forest. Then he notices everything in the forest has grown huge. He and Luna give the potion to the Mutants, who sprinkle it around Cats Lair. The Mutants also capture Lynx-O and Snarf. But while the Mutants are preparing to transfer Lynx-O and Snarf from their cell, a mouse in the cell who Snarf had befriended gets some of the potion and attacks the Mutants. That lets Lynx-O and Snarf analyze the potion and come up with an antidote. Meanwhile, Lion-O, Pumyra, and the Thunderkittens are fighting off huge bugs in the forest that has grown around Cats Lair. Lynx-O and Snarf arrive, sprinkle the antidote over the forest, and then watch as everything turns back to normal.

Tired of constantly being bested by the Thundercats, the Mutants have Mumm-Ra raise their spaceship and salvage their vehicles.

Mumm-Ra tricks Lion-O into using the Sword of Omens against Tygra, causing the blade to break in half and lose its powers. The only way Lion-O can restore the Sword is to venture into a volcano and have the Inflamer reforge it. But the Inflamer requires a payment of gold... Has Lion-O taken on more than he can handle?

Two Bolkins (sheep-like beings from Third Earth) unleash the ghost of Grune the Destroyer, a renegade Thundercat who once terrorised Third Earth and now turns his attention to the Thundercats.

Lion-O, Panthro, and the Thunderkittens take the Whisker, a new flying vehicle, to the Churning Rocks to rescue the Thunderian refugees who had called from there. The Thundercats get captured by Two-Time, a robot with 2 heads. Two-Time takes them aboard his spaceship, Dome-Down, and the Thundercats see that he has also captured the refugees. Lion-O defeats Two-Time and the refugees are freed. Meanwhile, Lynx-O, Cheetara, and Bengali spot Mumm-Ra near the Churning Rocks, and inform Lion-O of this. Lion-O, Panthro, and the Thundekittens head to the Churning Rocks and confront Mumm-Ra, who is in the form of Jaga again. They break Mumm-Ra's spell (again) over Jaguara, who had temporarily repaired the Gyroscope. Lion-O defeats Mumm-Ra, but Mumm-Ra reminds them all that eventually the planet will be destroyed without the real controls, which he still has...

Mumm-ra finds the Totem of Dera (a part of the T-cat treasure) which has special healing powers and can bring inanimate objects to life. He gives it to Vulture-Man and the Mutants so they can make a device to destroy the T-cats. After making the device, the mutants decide to test it near a swamp. At Cat's Lair, Lion-O sees that there is some mutant activity near the swamp. He, Wilykit, and Snarfer decide to check it out. When going to the swamp, the Hovercat is brought down by a swamp monster made by the device. The Hovercat crashes in the swamp, and Lion-O gets intoxicated by the deadly swamp water. Jaga appears and tells Snarfer that he must get the Totem of Dera to heal Lion-O. Snarfer gets the Totem and succeeds in healing Lion-O. Lion-O calls on the T-cats to try to kill the swamp monster. When all their weapons prove ineffective against the monster, the T-Cats come up with the idea to dissolve the monster in water and they succeed in defeating it.

The Thundercats capture the Lunataks and, tired of dealing with their evil ways, decide to exile the Lunataks to Exile Isle, an island in space far away from Third Earth. When the Lunataks arrive, they meet up with Captain Cracker, a pirate who the Thundercats also exiled. Together, the Lunataks and Capt. Cracker send out a distress signal to a passing ship. When the ship comes near the island, the Lunataks send up a cloud of fog, which makes the ship crash. They use the engines of the ship to push the planet out of orbit and towards Third Earth. Snarfer, on his way home from Thundera, crashes on the island when it runs into him. Lion-O goes to rescue Snarfer and stop the island, because it has a deadly gas that will blow up if it enters Third Earth's atmosphere. He goes without the Sword of Omens. He gets cornered by Capt. Cracker, but the Sword awakens and flies to Lion-O, without him even calling it. He then uses dirt to stop the engines, and the planet/island eventually returns to

Micrits, a tiny race of human-like figures, happen to live right outside Cats' Lair. Unaware of their existence, Lion-O manages to continuously step on their village and destroy their homes. Upset at this disrespect, the Micrits decide to take a stand and manage to trap Lion-O. With the Thundercat Lord in trouble, the Mutants attack Cats' Lair. After much talk, Lion-O manages to convince the Micrits that he is a "good guy" and convinces them to let him go to help save his friends. Once again, Lion-O saves the day, and befriends the Micrits.

Jaga is captured by Nemex, an evil being in the Astral World, and Lion-O tries to find a way to rescue him. Third Earth legend says that the only person who can transport anyone to the Astral world is the evil Nether-Witch. Little do the Thundercats know that Mumm-Ra and the Nether-Witch are one and the same. Mumm-Ra traps Lion-O in the Astral world, and Lion-O sets out to save Jaga. While escaping the Astral prison, Lion-O and Jaga save an old sorcerer named Brodo who has been imprisoned in the Astral Prison for centuries. As thanks, Brodo sends Lion-O back to his own dimension.

When Snarf and a young unicorn are captured by the pirate Hammerhand and his crew of Berserkers, Lion-O goes to rescue them.

With their supply of Thundrillium running low, the Thundercats set off in search of a fresh supply. Tygra detects a large deposit in a cave and goes to investigate - unfortunately, he has entered the Cave of Time and anyone who ventures in there will age rapidly until they die. His only hope is that Cheetara's speed will be fast enough to allow her to escape the Cave's effects.

Lion-O and the other Thundercats arrive and save Lynx-o and the Thunderkittens from Red Eye and Tug Mug. The Thundercats learn more about New Thundera, especially the dangerous places affected by the moons of Plundarr where the Lunataks come from. The Thundercats must develop special equipment and clothing to counter those dangers. Also, they learn that all the snarfs have been turned into slaves and Snarf and Snarfer want to rescue them no matter what the cost. Vultureman learns of the Thundercats plan, so he abandons the other Mutants and takes the Rat-Star. But Slithe has snuck aboard. Right after the Feliner takes off, the Rat-star ambushes them and it seems all over for the Thundercats aboard the Feliner. Lion-O uses the sword to free everyone and along with Ben-Gali and Wilykit on the HoverCat, go after the Ratstar and it crashes on Hook Mt. The Thundercats leave Third Earth's atmosphere and Lynx-O tells him that Mumm-Ra has already located the Sword of Plundarr.

Mumm-Ra summons the great samurai Hachiman to seek and destroy Lion-O. He tells Hachiman that Lion-O and the Thundercats are destroying his planet. Hachiman and Lion-O confront each other, but their swords refuse to draw on each other. They become allies and hope to destroy Mumm-Ra together. Enraged, Mumm-Ra summons another warrior, a ninja, to sabotage the Thundercats, and retrieve Slithe, whom they have captured.

On the second day of his trials, Lion-O must race Cheetara through the dangerous lands of Third Earth. Although Cheetara is by far the fastest among the Thundercats, her speed can only last for a short time period. Lion-O takes a shorter but more dangerous route to make up for Cheetara's advantage.

Mumm-Ra tells Aluro that the Egora Talisman will give whoever possesses it the power of extreme self-confidence. Aluro finds the talisman and uses it, along with his own powers of hypnotism, to "take away" the Thundercats' self-confidence, leaving them hopeless and confused. Only Snarf remains and it is up to him to defeat Aluro and restore the Thundercats.

With only Lion-O and Snarf guarding the Lair, Mumm-Ra decides this is a perfect opportunity to invade the Lair, so Ma-Mutt captures Snarf and Mumm-Ra switches Snarf and Ma-Mutt. Ma-Mutt (who now looks like Snarf) goes to Cats Lair and gives Lion-O some poisoned candy fruit. Lion-O becomes ill and realizes that this Snarf is really Ma-Mutt and Mumm-Ra arrives and defeats Lion-O. Snarfer's bad dream of Snarf becoming a dog causes him, Ben-Gali, and Pumyra to go to Cats Lair, but Mumm-Ra lays a trap for them. He sends Ma-Mutt to get Snarfer and Lion-O becomes better again and distracts Mumm-Ra. When Lion-O summons the other Thundercats, Snarf (who looks like Ma-Mutt now), using Mumm-Ra's chant that changes Mumm-Ra into the everliving, becomes... Snarf-Ra the everliving and he rescues Ben-Gali, Pumyra and they in turn rescue Snarfer from Ma-Mutt. Then Snarf-Ra challenges Mumm-Ra and defeats him. After the battle is over, Lion-O uses the sword to restore Snarf to his original state.

Vultureman creates a weapon that shoots pure Thundrainium in hopes of destroying the Thundercats. His first victims are the Thunderkittens who fall into a deep cavern and become injured. Lion-O and Snarf search for the missing kittens. Meanwhile Vultureman must get more Thundrainium from Chilla in Darkside and is also ordered by Slithe to fix the Mutants' machines. The Thunderkittens are saved by a Wollo and they discover that the Wollo village has been ""iced"" and they are captured and used as bait to lure Lion-O. When Lion-O and Snarf arrive, they are shot down by Vultureman's weapon and Lion-O becomes weak and summons the Thundercats. Just as Vultureman is about to finish off Lion-O, Ben-Gali arrives, wrecks Vultureman's weapon and drives the Mutants and Chilla away. Lion-O then uses the sword to restore the Wollo village.

Monkian goes to Mumm-Ra and agrees to give him anything if Mumm-Ra will make him powerful enough to rule Third Earth. Mumm-Ra agrees, and gives him Power Spheres which make him super strong and give him super weapons. He freezes all the Thundercats, then defeats Lion-O and takes the Sword of Omens back to Mumm-Ra. Mumm-Ra takes it, and then says that Monkian's part of the bargain will be that he can keep the spheres, but he has to stay in Mumm-Ra's pyramid for all eternity. Walls surround Monkian, and every time he breaks them down, a new set of walls shows up. While Monkian and Mumm-Ra are arguing, Lion-O retrieves the Sword and frees the other Thundercats. Monkian gives up his power to be free again.

Vultureman creates a weapon that shoots pure Thundrainium in hopes of destroying the Thundercats. His first victims are the Thunderkittens who fall into a deep cavern and become injured. Lion-O and Snarf search for the missing kittens. Meanwhile Vultureman must get more Thundrainium from Chilla in Darkside and is also ordered by Slithe to fix the Mutants' machines. The Thunderkittens are saved by a Wollo and they discover that the Wollo village has been ""iced"" and they are captured and used as bait to lure Lion-O. When Lion-O and Snarf arrive, they are shot down by Vultureman's weapon and Lion-O becomes weak and summons the Thundercats. Just as Vultureman is about to finish off Lion-O, Ben-Gali arrives, wrecks Vultureman's weapon and drives the Mutants and Chilla away. Lion-O then uses the sword to restore the Wollo village.

Mumm-Ra hires Captain Shiner no send a fake distress signal to the Thundercats. With their new vehicle, the Feliner, the Thundercats set out into deep space to help the "ship in distress". When they arrive, Shiner captures Lion-O and the Sword of Omens. He gives the Sword to Mumm-Ra, and Mumm-Ra throws it into a black hole. Cheetara returns to Third Earth to get Panthro. They rescue Lion-O, and seize Shiner's ship. Panthro sets a course into the black hole to recover the Sword. They enter, and must battle the robotic city of lost space ships to recover the Sword of Omens and escape.

Mandora, on space-patrol, encounters an old pirate ship which doesn't meet inter-galactic standards. She boards the ship, arrests the pirate, and sends the ship to a space prison . Little does she know that she has boarded the Jolly Roger, the home of the evil Captain Cracker. Mandora is captured by the creature. Lion-O intercepts one of her distress calls, and must go into space to save her -- easier said than done, as Cracker orchestrates a prison break.