The Z-Fighters must stop a mad scientist out to take over the world.
The evil Dr. Kochin uses the dragon balls to resurrect his mentor, Dr. Wheelo, in an effort to take over the world. Dr. Wheelo, his body having been destroyed by the avalanche that killed him fifty years before, desires the body of the strongest fighter in the world as his new vessel. Believing Roshi to be the world's strongest warrior, Dr. Kochin abducts Bulma and forces Roshi to surrender himself to save her. When Goku hears of their abduction, he goes to their rescue.—page8701
The evil Dr. Kochin has gathered the Dragon Balls in the Tsumnisumbri Mountains where the ice never melts. Using the Dragon Balls to summon Shenron, Dr. Kochin wishes for Dr. Wheelo and their laboratory to be thawed from the ice. In response, Gohan and Oolong use the Dragon Radar to track down the Dragon Balls, however are ambushed by the Bio-Men. Piccolo, who has been training in the area saves them, but is then incapacitated by three unknown fighters. Gohan and Oolong are knocked unconscious in the ambush and wake up later to return home after Gohan promises Oolong to keep their trip a secret.
Dr. Kochin and his Bio-Men show up at the Kame House, requesting the presence of Master Roshi, who is with Bulma and Oolong. The Bio-Men demand that Roshi come with them, but he refuses, easily defeating the Bio-Men that attack him in response to his refusal. Dr. Kochin then appears, revealing that he is looking for the world's strongest fighter, and when the remaining Bio-Men threaten Bulma's life, Roshi reluctantly agrees to go with them. A terrified Oolong makes his way to Goku's house and tells him what happened. Goku sets off on the Flying Nimbus to rescue Roshi and Bulma.
Meanwhile in Dr. Wheelo's laboratory, Roshi is tested to see if he is the strongest fighter by facing Dr. Kochin's three Bio-Warriors, Kishime, Misokatsun and Ebifurya. Roshi manages to put up a good fight, however is ultimately defeated. A restrained Bulma then informs Kochin that Roshi is no longer the strongest fighter anymore and says that she knows someone a lot stronger than him, alluding to Goku. Kochin finally reveals his plan for Wheelo's mind to take over the body of the strongest fighter and enact his plan for world domination.
Gohan also sneaks out of the house against his mother's wishes and follows Goku, who arrives at Wheelo's fortress. He is attacked by the Bio-Warriors, who he manages to defeat with the help of Gohan and Krillin who arrive shortly after. Goku then confronts Dr. Wheelo, demanding that he release Bulma. Suddenly, Piccolo, who has been brainwashed by Wheelo appears and attacks Goku, engaging him in a fight. Gohan becomes enraged and unleashes massive amounts of power, destroying much of the laboratory, as well as the brainwashing device on Piccolo's head. A shocked Dr. Wheelo breaks out into his robot body free from the wall, causing Dr. Kochin to fall to his death down an energy shaft. Krillin frees Bulma, and the real battle begins.
Dr. Wheelo engages Goku, Piccolo, Master Roshi, Gohan and Krillin, defeating them all. A weakened Goku powers up and fires a Kamehameha, blasting Wheelo into space. Goku then forms a Spirit Bomb, while the others distract Wheelo as he shoots ki blasts towards the Earth in an attempt to stop it. Goku unleashes the Spirit Bomb, defeating Dr. Wheelo who is completely destroyed.
