Gohan gets Bulma to make him a new costume for the World Martial Arts Tournament, and Vegeta announces his entry into the tournament. Also, Goku announces that he will be allowed to come back to Earth for one day to compete, and Gohan, while on the way to tell his friends of Goku's return, stumbles onto the set of a Great Saiyaman movie.
Gohan teaches Goten and Videl to fly; Goku trains in Other World as King Kai challenges South Kai to enter his new fighter in the World Martial Arts Tournament with Goku; Vegeta and Trunks train in the gravity chamber.
After failing to woo Videl, Sharpener tries to discover the identity of Saiyaman as all of the fighters attempt to earn a spot in the World Martial Arts Tournament by scoring highly on a machine that measures striking power.
Having won the Junior World Martial Arts Tournament, Trunks gets to fight Mr. Satan in an exhibition match. Also, as the Z Fighters prepare for their own matches, they meet two other mysterious fighters.
Goku returns from Korin's Tower with some senzu beans, and Gohan takes them to Videl; Mr. Satan stays with Videl in the hospital; Spopovitch and Yamu monitor the power levels of the other fighters in the tournament; Gohan and Kibito get in the ring.
After Gohan goes Super Saiyan, Spopovitch and Yamu drain his energy and fly away. Afterward, the Z Warriors follow them to see where they're going, and the mystery behind the recent events is explained to them by Shin and Kibito.
Start of the "Babidi Saga". The Z Fighters follow Spopovitch and Yamu to Babidi, and, while observing their meeting, they see some of Babidi's other henchmen. Back at the tournament, the crowd grows restless while waiting for the next fight.
The Z Warriors wait on the Stage Three opponent, Dabura, as he meditates to gain strength. Back at the tournament, the five remaining fighters--Killa, Jewel, Mr. Satan, Mighty Mask, and Android 18--begin a battle royale to determine the winner of the tournament.
The Z Fighters continue to wait on Dabura, who is still meditating. Back at the tournament, Android 18 fights Goten and Trunks (disguised as Mighty Mask) in the battle royale, as Mr. Satan sits back and watches.
Majin Buu easily pummels Dabura; Goku tries to convince Vegeta to stop fighting with him so that they can concentrate on Majin Buu; Mr. Satan reflects on his experiences with the Z Fighters, and he is accosted by reporters; Babidi commands Majin Buu to kill Gohan and the Supreme Kai.
Gohan and the Supreme Kai fight Majin Buu; Mr. Satan attempts to fly; Dabura, realizing how dangerous Majin Buu is, tries to convince Babidi to reseal him before it's too late; Trunks and Goten reach the battle site.
Having already found the first six dragon balls, Yamcha, Roshi, Android 18, Bulma, Chi-Chi, and Videl search for the last one. Piccolo and Krillin take Trunks and Goten to the Lookout to recover, and they talk with Dende about the current situation. Babidi and Majin Buu run amok and Goku wakes up.
Goku, Piccolo, Krillin, Mr. Popo, and Dende discuss strategy for defeating Majin Buu, and Goku explains the Fusion Technique, which he learned in Other World; Majin Buu causes trouble at an amusement park; Bulma uses the dragon balls to call upon Shenron, the eternal dragon.
Kibito looks for Gohan and the Supreme Kai; Majin Buu causes trouble at a bakery; Goku tells those who do not know of Gohan and Vegeta's fates; Babidi telepathically communicates his plans and desires to everyone on Earth.
Babidi and Majin Buu continue their reign of terror as they fish for the whereabouts of Trunks, Goten, and Piccolo. Trunks and Goten explore the Lookout. Gohan arrives on the Planet of the Kais with Kibito and the Supreme Kai, and he is told of the Z Sword.
Videl refuses to believe that Gohan is dead; Gohan removes the Z Sword and tries to wield it; Goku begins preparing Trunks and Goten for the Fusion Technique; Majin Buu destroys another city; Mr. Satan tries a new method of learning to fly, and his fans beg him to defeat Majin Buu.
Trunks and Goten practice raising their power to the same level for the Fusion Technique; Mr. Satan reassures the crowd; Babidi discovers that Trunks lives at Capsule Corporation, so Goku heads off Babidi and Majin Buu while Trunks races home.
Back in Other World, Goku finds Gohan on the Planet of the Kais and tells him what's been happening on Earth; Piccolo takes over the duty of training Trunks and Goten for the Fusion; Majin Buu befriends a blind boy.
After Gohan accidentally breaks the Z Sword while testing its strength, an old Kai who was trapped inside the sword is released, and he promises to awaken Gohan's sleeping powers. Meanwhile, Trunks and Goten continue practicing the Fusion Dance.
After several mess ups, Trunks and Goten finally fuse correctly, and the new entity, Gotenks, goes after Majin Buu, who is busy destroying ships. Meanwhile, Old Kai continues the ceremony to unlock Gohan's sleeping powers.
Having been defeated easily by Majin Buu in their first battle, Trunks and Goten practice the Fusion Technique with renewed vigor; Mr. Satan emerges from his training facility and goes to Majin Buu's house; Old Kai finishes his ceremony to awaken Gohan's sleeping powers.
Start of the "Fusion Saga". In a rage, Mr. Satan fights the two thugs. Majin Buu heals the puppy, rebuilds his house, and relaxes with Mr. Satan. Gohan grows impatient with waiting, and he tells Old Kai about Bulma. One of the thugs comes back to cause trouble for Majin Buu and Piccolo scolds Trunks and Goten for being gone for too long.
Gotenks uses the Super Ghost Kamikaze Attack against Majin Buu; Goku can't sense Gotenks' or Majin Buu's energy, and he realizes that they're fighting in the time chamber; Mr. Satan and Bee wander the desert and think about their time with Majin Buu.
As Majin Buu continues to fight Gohan, he realizes that he can't win, so he self-destructs, hoping to take Gohan with him. Afterward, Gohan, Piccolo, Goten, and Trunks search for Dende, and they find Mr. Satan and Bee wandering in the desert.
Vegito continues fighting Majin Buu, who is getting frustrated and is using the special attacks of the people he has absorbed. In Other World, Videl tries to convince everyone that Gohan is still alive.
Vegito is turned into candy by Majin Buu, but he continues to fight; King Kai considers sending Krillin and Yamcha back to Earth to help in the battle; King Yemma tells Fortune Teller Baba the story of how he convinced Vegeta to help.
Goku and Vegeta befriend a family of worms living inside Majin Buu. They continue searching for Trunks, Goten, Gohan, and Piccolo, but instead they find versions of them that Majin Buu has created in his mind, and they must fight them. Meanwhile, Majin Buu eats everything he can find.
Mr. Satan tries to convince himself that everything that has happened is just a dream; Majin Buu destroys lots of planets while looking for Goku and Vegeta, who are trying to form a plan revolving around the use of the dragon balls.
Vegeta calls upon Earth's population to give up their energy to Goku, who begins charging his Spirit Bomb. Meanwhile, good Majin Buu continues to fight evil Majin Buu. Also, the people of Earth celebrate their new lives.
It is ten years after the defeat of Majin Buu. Trunks shows up at Goku's house, where he talks to Chi-Chi, Gohan, and Videl. He then goes out to the country to meet Goku and Goten, who are training. Vegeta and Bulma also arrive, and Goku tells everyone of his plans to enter the World Martial Arts Tournament because he thinks there will be a serious challenger this year. Also, Pan, the daughter of Gohan and Videl, arrives and announces her plan to enter the tournament as well. Later, everyone arrives at the tournament and gets settled.
The competitors who have made it past the preliminary round of the World Martial Arts Tournament draw numbers to determine who will fight whom in the next round, and the fights begin as Pan faces Wild Tiger and Goku faces Uub.