Thundarr, Ookla, and Ariel are in pursuit of a mummy-like Janus after he and a race of hawk mutants attack villages and the train route of Tye (the former swamp urchin from "Harvest of Doom"). The group is in for a surprise when it turns out Janus is actually Gemini (the two-faced wizard from "Secret of the Black Pearl") in disguise seeking revenge on Thundarr. Tye, from "Harvest of Doom", returns as a train driving "businesswoman".

Thundarr, Princess Ariel, and Ookla are caught up in a battle between the wizards Sholow and contestants Basim, Skorpos and Chom who seek the Helmet of Power. Thundarr ends up having to side with the wizard Sholow when he threatens a group of villagers.

A spaceship containing an alien vampire lands on Earth. The alien captures Princess Ariel and all the villagers in the ruins of Lakeside Amusement Park hidden under the snow and ice of the Rockies as a source of its food.

Thundarr, Princess Ariel, and Ookla come to the aid of a race of amphibious Amazons led by the deposed Queen Diona who has been usurped by Stryia, an evil half-human, half-shark wizard-queen who plans to conquer both the land and seas with her shark legion army.

During a battle with Yando (a supposed wizard with unusual magic), Thundarr is struck by red negative lightning which significantly diminishes the power of his Sunsword. The weapon can be restored at the nearby Pool of Power, but it is stolen by Yando who seeks to have the Sunsword's power for himself.

The wizard Skullus and his soldiers are enslaving villagers living in a ruined oil refinery and using them to attack the fortress of his enemy, the equally evil wizard Octagon.

Thundarr, Princess Ariel, and Ookla encounter a train carrying Death Flowers (whose pollen can hypnotise both humans and Moks) being transported by the Carocs (a race of crocodile people) to a wizard.

Thundarr, Princess Ariel, and Ookla battle the evil wizard Vashtarr when he steals the Crystal of Prophecy that can give the details of his downfall. When it shatters in his efforts to retrieve it, the prophecy is foretold as they learn three women will unite to defeat him. One is Maya, an element-shifter buried in the ruins of the old city of Endorr. Another is Cinda, a hermitic barbarian living in the Canyon of Death whose staff grants her great strength. The last is Valerie Storm, a fashion model from Old Earth who is abducted and taken prisoner by Vashtarr himself.

Simius and his fellow Man Apes assemble salvaged parts of a movie studio's giant robotic gorilla in a plot to terrorize the local villagers.

The trio investigate a sector called the Mystery Zone where several ships get wrecked on an island. They learn the evil witch Circe is responsible as she needs a young sorceress to overcome a curse in which she will turn to stone if she leaves the island. When Ariel arrives with Thundarr and Ookla, Circe gets her opportunity as she switches bodies with her and becomes a threat to the others as she tries to leave the island.

Thundarr's friend Thorac is accused of stealing a village's fuel and is about to receive a death sentence (by being boiled alive over a geyser) when the barbarian rescues him. Thorac is granted a reprieve when Thundarr and the group investigate the crime, eventually learning the town's sheriff Korb is in league with the evil wizard Artemus. Artemus had stolen the fuel to power his Death Ship and gain the approval of the Council of Wizards.

The evil wizard Crom threatens a tribe of humans at the Alamo. They can protect themselves by using a sophisticated Guardian machine that utilizes flying robot drones that can disable the wizard's laser tanks. However, it blows a circuit and cannot be replaced as circuits are no longer produced. Their only hope is to infiltrate Crom's lair in order to use his moon dial, which sends them to Old Earth. In the 20th century, Thundarr, Ookla and Ariel are aided by a little girl named Samantha, who helps them obtain a fresh circuit. The trio return to New Earth and prepare for battle with Crom, but are glad they had a chance to see the preapocalyptic world.