Bojack is the main villain of the movie. His goal is to conquer the universe and destroy all those that stand in his way. According to King Kai, he was sealed by all four Kais in a star, but when Goku teleported the devolved, ready to self-destruct Cell to King Kai’s planet, killing him, the seal broke, allowing Bojack to reap destruction upon the Earth. The movie starts with a big martial arts tournament in which 200 elite fighters will compete, including Yamcha, Tien, Piccolo, Gohan, Future Trunks, and Krillin. The winner will get to face the famous champion “Mr. Hercule” (also known as “Mr. Satan” in the Japanese version). Goku is shown in Other World, watching the tournament with King Kai. The first round consists of 8 contests – 25 fighters are put on each fighting “stage”, and the last one standing on each stage will advance to the semi-finals.
Tien, Piccolo, A 13 year old Gohan, Krillin, and Future Trunks are among the 8 who advance. As the advancing fighters’ names are announced, Mr. Hercule is shown getting increasingly nervous, as he is aware of the prowess of these fighters. He begins looking for a way to back out of the fighting, eventually claiming to have a “stomach ache”. In the meantime, the semis pit Tien against Future Trunks and Krillin against Piccolo. Future Trunks beats Tien. Piccolo is disgusted by the lack of a challenge in this supposedly “elite” contest and forfeits against Krillin. Gohan, Krillin, and Future Trunks are among the 4 who advance to the finals, in which each of them will compete against a fighter from elsewhere in the galaxy. However, as the alien fighters are revealed, the fight promoter realizes that these are not the fighters that he had recruited for the contest.
Everyone soon begins to realize that there is something wrong as Trunks is challenged by Kogu, Krillin faces Zangya, and Gohan confronts Bujin. During this time, Mr. Hercule is in the rest room, thinking about how he got himself in this mess, but after looking at his belt he realizes that the people need him and, in an uncharacteristically brave mood he goes out and gets slammed into a space pod and sent to the fighting. During his fight against Kogu, Trunks transforms into a Super Saiyan, shatters Kogu’s sword, and shoves his fist right through Kogu’s abdomen, killing him. As he turns to leave, he is struck down in one blow by an unknown foe. Far away, Vegeta feels this power and knows something is wrong. Gohan continues his fight with Bujin until he is led out to where Krillin and Trunks are. After inspecting his fallen friend, Bojack introduces himself and tells Gohan his plans to rule the universe as his revenge. Yamcha and Tien turn up to fight but are defeated by Bujin, Bido and Zangya. Seeing his friends fallen, Gohan transforms into a Super Saiyan and fights Bojack’s henchmen while Bojack watches on in amusement. Gohan is beaten down and Bojack powers up an attack to finish him off, although it is deflected by Piccolo, who has come to Gohan’s aid. Trunks comes back into action and they both challenge Bojack. After a period of fighting Trunks’s sword appears; Trunks catches it as Vegeta enters the fight and transforms into a Super Saiyan, quickly setting on Bojack.
During this, Trunks thinks that Vegeta would only ever fight when it meant him surpassing Goku’s strength, and Trunks realizes that Vegeta has truly changed. While Vegeta fights Bojack, the rest fight against his surviving henchmen. During his fight against Vegeta, Bojack beats Vegeta down and transforms. Gohan rushes to Piccolo’s aid, but Piccolo tells him to not worry about him and fight Bojack. Bojack challenges Gohan to a fight and beats him thanks to the aid of Bido and Zangya’s Untrapped ropes, which drains Gohan’s energy away, but Gohan is freed when Mr. Hercule’s incoming pod distracts them all. Annoyed at this, Bojack powers up an attack and blasts Mr. Hercule’s pod, causing him to fall to the ground. Trying to save him, Gohan is struck down by Bojack’s henchmen.
On Snake Way with King Kai, Goku can’t watch any more and, using his Instant Transmission, teleports himself to the fight and punches Bojack before he can finish Gohan off. Surprised, Bojack falls to the ground. After a few words of advice, Goku places his son on the ground safely and disappears. Gohan, taking in his father’s words, gets back and turns to Bojack with fire in his eyes. Gohan transforms into Super Saiyan 2, surprising Bojack and his crew. Gohan beats Bido and Bujin each in one hit, breaking them both in half, and Zangya is killed when Bojack uses her as a shield from Gohan. The angry young Saiyan then slams his fist into Bojack’s stomach, blowing a hole in his stomach and out through his back. As a last resort, Bojack powers up his Galactic Buster and Gohan prepares a Kamehameha. The energies clash together and in the blinding light Bojack is killed. Gohan, exhausted, falls backwards laughing as Goku praises him from Other World, and King Kai jokes that Goku broke the rules of going back to Earth while dead. After the events, everyone is in hospital watching the news that Mr. Hercule is a “true hero” who defeated the alien intruders; this results in several jokes. As in Super Android 13!, the film closes with Piccolo and Vegeta on the roof, arms folded and backs turned to each other, isolating themselves from the celebration.