Kaito Gōshō, who helps out others with his friends Mitsuo Zaizen and Fukuta Kanemaru, rushes to the aid of their companion, Nagare Amano, who is being bullied. Kaito manages to get back Nagare's wallet by beating one of the bullies, Raigo Raigou, in a Hero Battle, a digital battle game using rented battle suits powered by support from spectators. Later that day, Raigo brings his older brother, Shuuto, to challenge Kaito to another match for revenge, deciding to make Kaito his henchman should he win. However, during the middle of the battle, the rental period for Kaito's 'Bad Boy General' suit expires, leaving him naked and defenceless.

Kaito has been burdened with a ten billion yen debt in exchange for Enter the Gold. Big Money Company's Mitsuo Zaizen and Fukuta Kanemaru, and his sister Ai Gosho are in a panic! However, Kaito declares with sunny luminance that he'll pay back the debt. Then, Nagare makes a certain proposal. "I want to have a hero battle with you."

With it decided that they will participate in the Big Money Hero Wars, Kaito and the others have their eyes on breaking through the preliminaries. But first, Kaito heads to his familiar barber to get some upkeep on his regent hairdo. However, a new beauty salon has stolen his customers and driven him to close shop.

Kaito and gang arrive at Big Money Bay to catch some fish for dinner where they meet the third heir to "The Fish Samurai Shop," the oldest shop in the Big Money Fresh Fish Market Castle: Isshin Uminari. The two of them immediately hit it off, but when they learn they are both in the Hero Wars, they clash in a Hero Battle! Whose passion will burn brightest!?

A rival appears for Big Money Company! Lead by Hana Akinai, their name is "Money-grubbing Corporation." Hana has cultivated the girl's "Detention Club," where they study with their clients into a huge success. Since Kaito hates to lose this gets his competitive streak all fired up. He starts the "Big Money Detention Club," but...

Kaito and the others go to Fuji to help Fukuta's uncle and aunt pick tea leaves, in order to earn money to pay off their debt. Meanwhile, Nagare stays at home under the pretense of having to attend cram school, thinking over what he wants to do with himself. Later that night, Mitsuo notices something peculiar about a Snipe Sweeper participating in the Hero Wars. The next day, as Kaito and Mitsuo get into an argument with each other, Fukuta challenges both of them to a three-way Hero Battle between Kaito's Enter the Gold, Mitsuo's Game Console Beep Boop, and Fukuta's Tea Picking Cat. Mitsuo and Fukuta both team up against Kaito, but he throws their attacks back at them, and by the end of the match, everyone has forgotten why they were angry. Upon returning home, Kaito and the others learn Nagare is participating in the Hero Wars.

Nagare, who is once again approached by the mysterious figure, Money Ghost, accepts his contract for power, becoming enveloped in digital energy and having his personal data removed from the city's network. Noticing a disturbance in the system, Sennen sends a mail out to Kaito, Mitsuo, and Fukuta. The next day, the three boys are disturbed to find no one besides them know who Nagare is, finding all records of him have been wiped. Speaking with reporter Maki Kashii, the boys hear a rumor about people being dragged into the Hero Bank airspace. Later that day, Kaito receives an e-mail from someone who knows about Nagare, calling the boys to meet with them at Gappolis.

Sennen appears before Kaito and the others, explaining how he protected their memories of Nagare from being rewritten and suggesting Kaito undergo training in order to become stronger. Shishio Torai, a delinquent with a crush on Ai, offers to help Kaito in this regard, though it all proves pointless since he isn't using a Hero Suit. Afterwards, Kaito and co. are invited to a 'Hero Wars Seminar' by Kasumi Kamimaki, who is soon revealed to be a scam artist who had conned many victims. Angered by this, Kaito challenges Kasumi to a Hero Battle against his Hero Suit, Trick Suit. As Kasumi uses various tricks and cheats to put his opponent at a disadvantage, Kaito, spurred on by the support of the scammed victims, recalls Shishio's training and manages to win the match, after which Kasumi is arrested.

After winning a lottery in the shopping center, Kaito, Mitsuo, Fukuta, Ai, and Kaito's grandfather Zōan head to a hot spring inn, where Hana and the Gamitsui Corporation are coincidentally helping out. Later that night, Kaito accidentally breaks his Bankfon G after being spooked by Ai. Afterwards, Kaito runs into Hana, who explains she is trying to help out the inn, which holds a lot of memories for her, to keep it from being sold to a developer, before accidentally spraining her ankle. The next day, the developer, Ageo Sokoo, comes and smashes the inn's entranceway, trying to coerce the owner into selling the inn. Wanting to protect Hana's memories, Kaito challenges Sokoo to a Hero Battle against his Hero Suit, Heavy Builder, with the inn on the line.

Fukuta gets into an argument with his prophecy-predicting mouse, Platina, after he gets special treatment concerning a fortune teller being essential to the team's victory. After storming off, Fukuta comes across a fortune teller named Tamako Futoi, who seems to be popular due to her predictions concerning Hero Battles. As Fukuta decides to get his fortune told, he ends up buying a pricey fortune telling slip machine from her in the hopes of competing against Platina, only to find its predictions worthless. Whilst trying to return it, Fukuta spots Shishio, who was conned by Tamako, trying to get his money back by fighting in a Hero Battle against her Shryne Maiden Hero Suit, but ends up losing and has to buy another item. As Kaito decides to go up against her for a refund on Fukuta's item, Tamako adds a rule stating that if Kaito loses, she will take Platina.

With the Hero Wars preliminaries nearing its end, Kaito struggles to find opponents willing to fight him. Whilst he and the gang go with Ai to a factory in Iron Town to get her fridge fixed, some delinquents appear and cause trouble but are handled by the manager Koutetsu's son, Tetsunosuke "Kintetsu" Kanagata, whose arms were replaced with robotic parts whilst protecting Koutetsu from an explosion. Kaito and Ai return the next day to thank Kintetsu and help him and Koutetsu out, later learning that the factory is in debt.

As Iron Town comes under attack by Cyber Emperor due to Kintetsu's family failing to pay off their debt, Kaito confront's the company's president, Deborah Kizaki, who claims to have purchased Iron Town and plans to turn it into a theme park. Kaito puts his Enter the Gold suit on the line to win Iron Town back from Deborah in a Hero Battle scheduled for the next day. As Deborah does a background check on Kintetsu, desiring to take the rights to his iron body, Kaito is approached by Sennen and brought to his hideout. Sennen warns Kaito that Deborah's suit, Baron the Euro, is a prototype designed to be more powerful than Enter the Gold. Later that night, as the news depicts Kaito's challenge to Deborah in a negative light, Isshin and Kintetsu pay him a visit to give their support. As the battle begins the next day, Deborah uses a poison ability to drain Kaito's strength, and despite Kaito's best efforts, he is overwhelmed by Deborah and loses the match.

As the demolition of Iron Town continues, Deborah acquires a patent for Kintetsu' iron body and sends one of his minions, Rohan Yuri, to capture him so he can mass produce it. With Kaito determined to rescue Kintetsu, Sennen informs him that Enter the Gold has some hidden abilities, but notes Kaito doesn't yet have the requirements to access them. Later, Maki, who had discovered the scathing new reports about Kaito were fake, mentions there are many dark rumors surrounding Debora, including being behind the explosion that injured Kintetsu, stating they need to find solid evidence to prove it. In order to distract Deborah so that Mitsuo and Fukuta can infiltrate his network, Kaito challenges him to a rematch, with Isshin and Koutetsu putting their own stakes on Kaito's victory. As Kaito is once again overwhelmed by Deborah's speed, Mitsuo and Fukuta manage to successfully access his files and expose them to the media.

On his way to the venue of the Hero Wars finals, Kaito and co. get a lift from a speed-loving man. As the tournament begins, Isshin, Hana, and Nagare clear their first matches. Kaito ends up pitted against the man he met earlier, former F1 racer Hayaiyen Messa, and his hero suit, The Grand Prix, whose speed proves to be a match even for Enter the Speed. Despite Enter the Speed causing a strain on his body, Kaito's determination to never give up allows him to overtake Hayainen and defeat him. Whilst returning home, Hayainen, who was burdened with a past accident that caused him to quit racing, decides to put it behind him and focus on improving his Hero Battle skills.

Kaito arrives at school to find that Li-Chi Long, a young Chinese boy he encountered at the Hero Wars venue, has transferred into his class. Long soon starts attracting attention with his academic and physical prowess, prompting Kaito to try and befriend him. He invites Long to his house to try Zōan's pickled produce, which reminds Long of his own grandfather, who he entered the Hero Wars for. To repay an earlier debt, Long decides to have a Hero Battle with Kaito using his suit, The All Powerful Ura Dragon, ahead of the finals. After a trade of blows and gags, the match ends in a draw, after which Kaito decides to make Long the Gappori Company's vice-president, unaware that he is actually under the employ of Nagare.

In the A-block of the Hero Wars, Kintetsu faces off against Rohan and his suit, The Dostorbrewski, but ends up losing against his powerful armor. Wanting to become strong enough to beat him, Kaito tries to follow Long's advice and become 'nothingness', with not much success. Whilst at a karaoke bar, Kaito runs into his next scheduled opponent, Tometoshi Kakarimachi, who accidentally damages his Bankfon, though chooses not to force him to pay for the damages after hearing his sob story, instead leaving the repairs to Long. The next day, Kaito battles against Tometoshi's suit, Hilaryman, and despite Tometoshi being a rather weak fighter, Kaito finds himself hassled by a bug that Long had secretly installed, causing his special attacks to damage himself.

After a meeting with Nagare, Rohan, and Money Ghost, Long is interrogated by Mitsuo and Fukuta over what happened during the previous match. However, they just assume that Long had simply struggled to fix Kaito's Bankfon properly and give him the more minor punishment of participating in the Detention Club for a day. The next day, Kaito faces up against Rohan, who reveals he is a member of the Gold Force. Despite Rohan's strength, Kaito becomes eager to have fun fighting him, winning the battle with some tactical job switches. As a result of Rohan's defeat, Nagare has him disappear, revealing to Kaito he is also a member of the Gold Force.

Sennen meets up with an acquaintance, who is acting as a spy for him, trying to learn more about Money Ghost. Meanwhile, Hana is lined up to face against Long, with the winner moving on to face Kaito in the semifinals. Later that day, Long spends the day helping out the Gappori Company with helping others, though is promptly reminded of his mission by Nagare. The next day, Sennen appears before Kaito and the others, revealing Long is a member of Gold Force, though Kaito refuses to believe him. As the fight between Long and Hana begins, Long is conflicted between his friendship with Kaito and his mission to get revenge for his grandfather's death, but in the end, he casts aside his emotions and launches a vicious counter-attack against Hana, continuing to beat on her even after he wins. As Long vows to meet Kaito in the finals, Hana soon picks herself up and focuses on sales to earn money.

As Kaito and the others argue with each other over Long, Isshin helps them cool their heads with a water gun fight. After the guy manage to clean the pool together, during which Isshin learns Nagare, his next opponent, was everyone's friend, everyone comes around to swim in the pool. Meanwhile, Long drops by Kaito's house to drop off some food, receiving some words of advice from Zoan. The next day, Isshin faces off against Nagare, hoping to open his eyes, but is no match for Nagare's overwhelming strength.

Kaito has doubts about facing Long, but receives some encouragement from Zoan after he brings some of Long's pickled vegetables. As the match between Kaito and Long begins, Long starts to hesitate when Kaito's dedication reminds him of his youth with his grandfather. However, Long's suit suddenly takes a life of its own, dishing out brutal attacks against Long's will. As Long fights against the suit's control, feeling betrayed by Money Ghost, Kaito understands Long's desire to have a fair fight, reminding him that people can smile whether they have money or not. After a final clash, Kaito wins the match, his feelings finally managing to reach Long, who disappears with a smile on his face after Nagare downsizes him.

As Money Ghost offers Nagare any wish he desires should he win the championship, Kaito finds a wallet Nagare gave him and asks Ai for some advice. The next day, as Nagare gets an early lead in his match against Kaito, he expresses his desire to surpass Money Ghost and fully remove himself from everyone's memories. However, Kaito reminds Nagare that even if he erases everyone's memories, the fact he existed will still remain. After managing to knock away Nagare's guns, Kaito uses the funds the Gappori Company had raised together to launch a powerful attack that wins the match and the championship.

While Nagare is taken to hospital following the battle, Kaito is awarded his championship prize and the opportunity to fight the world champion, Ryouta Arashiyama, and his hero suit Segalion. After the group get together at Kaito's house to celebrate his victory, the battle between Kaito and Ryouta begins, with both fighters evenly matched and Kaito emerging as the eventual victor. Following the match, however, it is revealed Ryouta was actually a virtual puppet created by Money Ghost, who announces the Hero Wars were all his plan in order to awaken a key. After Sennen chases him off, he takes Kaito and the others to a secret facility underneath their clubroom known as Gold Base. There, Sennen and his assistant, Hikari Takarano, reveal that Money Ghost is actually the creator of Hero Battles, Adachi Sumimori, who has sworn revenge against money for the tragedies it has brought. The group soon learn that Nagare has been kidnapped by Adachi, who plans to use him to overwrite the world.

After learning from Sennen about the Underbank cyberspace Adachi resides in, Kaito meets up with the Hero Bank company president, Kinzo Sengoku, who explains he is unable to give Kaito his prize because Money Ghost's interference has put his company in trouble. Just then, Adachi puts his plan into action, using Nagare's power to drain everyone's bank accounts and remove money from the world. He then covers the world in cyberspace and unleashes an army of Megalion Ghost Hero Suits to destroy the city. Learning the Megalions are made from data, Kaito and the others are able to use their Hero Suits to fight back, earning battle money from around the world. With more people joining the fight, Kaito heads towards the Underbank to rescue Nagare.

Learning that Long and Rohan are somewhere in the Underbank, the group split up, with Sennen arriving to help Kaito as he heads towards Nagare's location. Kaito is confronted by Adachi, who forces him into a match against his hero suit, The End of Money. Mitsuo and Fukuta manage to awaken Long and Rohan and together they join Kaito in battle, managing to knock Adachi back. However, Adachi brings out his ultimate hero suit, The Apocalypse, to fight back. Rejecting a world where working hard makes no difference, Kaito receives support from all over the world and unlocks a new suit, Enter the Hero, using it to defeat Adachi and return money to the world. However, the overwrite hasn't stopped, so Kaito heads on towards Nagare.

Nagare proves to still be hostile, as his new evolved hero suit, Justice Dollar, is revealed to be the one causing the overwrite, with Adachi planning to use his negative energy to convert the world into data. Learning Justice Dollar is the one controlling Nagare, Mitsuo and Fukuta manage to gather the data for Long's virus and have Kaito infect Nagare's suit with it, leading him to get hit by his own attack. Nagare starts to come to his senses, realising the folly of his ways, but is suddenly possessed by Justice Dollar's backup system, leading to one final clash between Kaito and Nagare, ending in a double knockout which stops the overwrite. As the city reverts to normal, Adachi stays behind to let Kaito and the others escape the Underbank before it collapses in on itself. While Kaito and Nagare rekindle their friendship, another boy watches over them.

Following the Money Ghost incident, Kaito, whose debt is waived by Sennen, uses his ten billion yen prize to help out his friends, using what's left over for a bath of Yummy Sticks. Three months later, the Gappori Company has grown in popularity, with people regularly challenging Kaito and Nagare to tag battles. Mitsuo in particular is pleased with how much money the company is earning, even making plans for a movie adaptation, though the others don't necessarily share his enthusiasm. Just then, a pig-like "money fairy" named Boochokkin emerges from Kaito's BankFon, demanding a lot of money to eat in exchange for an appearance in their movie.

Kaito becomes bewildered by the actions of Sekito, while Nagare notices he possesses his own Bank Register. The next day, as Kaito and the others accompany Ai to a supermarket opening, the market is suddenly attacked by another 'Tower of Seizure', bringing forth more Rampage Suits, Tick-A-Tack and Snap Shutter. As Kaito and Nagare struggle against their ability to stop time, they manage to use their abilities against each other and defeat them. Afterwards, Nagare confronts Sekito about who he is at school, but is seemingly crushed when he protects Kaito from a falling Tower of Seizure.

After being helped by Sekito upon being knocked out by the barrier Tower of Seizure, Kaito learns from Hikari that Nagare was most likely converted into data and absorbed into the tower rather than crushed. Meanwhile, in the market district, a strange man named Ryuuga Tennouji attempts to buy out the fishmongers and cause dispute among their business partners. Isshin attempts to fight against him, but Ryuuga quickly defeats him before using another Tower of Seizure on the fish market to seize all of its property. Upon learning of the situation, Kaito confronts Ryuuga and his hero suit, Like the White Tiger, which proves to be too powerful for even Enter the Hero, forcing Sekito to rescue him. As Kaito laments not being able to beat Ryuuga, a man calling himself the cabinet prime minister suddenly emerges from his toilet.

Kaito and gang take a business trip using the Warp Machine "Snuffed Out" to Osaka, the city of laughs, in order to beat Ryuuga of the Seven Gods of Suits! Under Ryuuga's control, Osaka has rule where following up a joke with a retort incurs a tax and punishment.

Kaito and the others are mistaken for enemies by Taiga and escape by warping through the toilet. They arrive in Kochi of all places! There they meet Turtle Company's Ryouma Ishin. Big Money Company promises to defeat Hyouri Aimu, the member of the Seven Gods of Suits who controls Shikoku, on the condition Ryouma resolves their misunderstanding with Taiga.

Sennen installs a reinforcement program for Enter the Gold so that Kaito can overthrow Ryuuga. Kaito returns to Osaka with Ryouma and meets Taiga once again. Taiga is stubborn and doesn't trust Kaito's invitation to defeat Ryuuga together.

The coalition between Kaito, with his evolved Enter the Prize, and Taiga lasts very briefly before Fukuta is kidnapped by Deborah Kizaki, who has gotten in close with Ryuuga behind the scenes. Taiga proposes a Gamble Rule with Fukuta on the line.

Kaito and the others come back to Big Money District for the first time in ages to a big surprise: Shishio Torai has become the prime minister! Ai and Zouan follow him obediently for fear of his overbearing behavior and the punishments for disobeying his laws. When Kaito and gang learn what is going on and rebel, Torai ups the ante even further! He holds an emergency press conference and makes a startling announcement!

An SOS arrives from the Okinawan resistance, and Kaito and company take a business trip to Okinawa! Everyone is in the mood to sightsee, likely because Ai has tagged along. Then, they all hear some strange sound, and Ai, Fukuta, and Mitsuo lay their desires bare and transform into money zombies! Danjirou Sastuma of the resistance movement, and the mysterious masked janitor "Justice Star" show up to help!

Kaito and Sekito escape from Bukimi and hide at the Yours Truly Company secret base while they wait for Nanten Minami to complete the anti-Resort Virus vaccine. Ai and Danjirou, brainwashed, appear there and launch an attack! Kaito and Sekito manage to get away thanks to Justice Star, but Kaito begins to show symptoms of turning into a money zombie...

An SOS arrives from Momiji Kurenai, and Big Money Company takes a business trip to Hiroshima! Their enemy this time is the lone female member of the Seven Gods of Suits, Benten Kureha. She seems to be plotting to use the money she has ripped off from everyone for something crazy. Kaito and gang head to the Tower of Bibel to infiltrate Benten's host computer system, but a number of traps await them inside!

Kaito and gang get incredibly close to capturing Benten, but ultimately fail due to Momiji Kurenai, an enemy spy. Their next strategy is an ambush on the Tower of Seizure. The group heads to Kureha Shrine, where the Tower of Seizure stands, but as they attempt to carry out their plan, the tower transforms into the giant robot, King Benten! Can they save Hiroshima from its rampage?!

This time it's a business trip to Nagoya. There, they are greeted by Hokosu Shachi, the member of the Seven Gods of Suits forcing everyone to cut back in rash ways. When confronted, Hokosu says, "If you beat me, I'll let you take my daughter!" The fight proceeds with a special rule where you gain battle money by proposing good ways to be frugal. Kaito is useless this time around, so Mitsuo takes his place and joins the battle with his eye on marrying into riches!

An emergency develops! All of the toilets in Big Money District have been frozen. Big Money Company panics: they can't use the toilet warp like this! Justice Star appears and tells them Himuro Touki of the Seven Gods of Suits is behind this scheme. Kaito and gang catch a ride on Ryouma's ship and take a business trip to Tohoku, where Himuro resides!

Due to enemy interference, their ship explodes! Kaito and the others are expelled from cyberspace and are scattered across Tohoku. Mitsuo, Fukuta, Boochokkin, and Ryouma join up and search for Kaito. Then a mysterious ghost appears and everyone panics! Elsewhere, Nagare discovers Sekito passed out, and then Himuro appears...

Kaito has finally been found, but he's lost his memory! He is taken back to Big Money District for the time being, but everyone is thrown through a loop when Kaito actually flushes the toilet, doesn't stick his butt in people's faces, and even starts speaking politely. Suddenly, Kyousuke Kakei, the strongest man in the Seven Gods of Suits shows up! Left with no choice, Sekito and friends accept his challenge.

Kakei's fierce attack leaves Kaito in a tight spot, and Himuro shelters him in a rift in cyberspace. He lands in the "cyber spirit world" which is composed of the malice of money-hungry fight leaders!

Kaito is saved by Sekito and safely returns from the cyber spirit world only to be swamped by crowds of people. Mitsuo recognizes this as a business opportunity and starts "Kaito's Supernatural Consultation Center," and it's a big success!

Sekito Sakurada has just started to fit in at Big Money Company. The others prepare a matching business card for him, but his position hasn't yet been decided.

Kakei destroyed the Gosho home and kidnapped Sekito! Kaito and gang head for the casino tower where Kakei awaits, but the five Seven Gods of Suits' Hero Suits they previously defeated are being pitted against Sekito.

Kaito has saved Sekito, and now he challenges Kyousuke Kakei, the last of the Seven Gods of Suits, to a Hero Battle. Kakei suggests they wager something: their lives!

Asuka Yagami, the Cyber Bureau secretary, was manipulating the Seven Gods of Suits behind the scenes all along! Yagami, who has transcended the barrier between real and digital, erects the Tower of Bankruptcy at the capitol and generates "money tornadoes" which begin to transform everything in Japan into money.

The Missiles of Seizure fire! While money typhoons are changing everything in the world into money, Kaito and gang head for cyberspace to stop Yagami with the legendary ten yen coins. However, the Prize Yen Dragon and Cosmic Dollar Dragon are helpless against Yagami. Just when all seems lost, the sun and moon's priceless friendship creates a miracle!

Yagami steals and absorbs everyone's Hero Suits including Credit Loan Wolf and transforms into his strongest form: The Phoenix Wolf! Kaito fights with everyone's hopes planted on his shoulders, and Sekito attempts to carry out his mission.