Bulma has invited everyone to a party at Capsule Corporation. Goku's family is ready to leave for the party. The only problem is that Goku is nowhere to be found. A frustrated Chi-Chi, Gohan, and Goten leave without him. While everyone's having a good time at the party, Goku is out on a mountaintop. He is looking after some eggs that are ready to hatch; Goku protects the eggs from the storm and predators. After the eggs hatch, he finally arrives at the party, which delights everyone.

Goku uses his Instant Transmission to deliver some Senzu beans from Korin. He gives the Senzu beans to Gohan. Gohan rushes to the infirmary to give one to Videl. Gohan gives a Senzu bean to Videl to restore her to full health. Gohan's identity as Great Saiyaman is revealed to his classmates after his bandana was blown off during his outburst. Gohan steps up to face against Kibito, who requests to see Gohan's Super Saiyan transformation. After Piccolo informs the other Z-Fighters of Shin's identity as the Supreme Kai, he orders Gohan to transform. Shin asks Goku and the others not to intervene. Right after Gohan transforms, Spopovitch and Yamu appear and hold Gohan down. Spopovitch and Yamu use a device to drain his Super Saiyan energy. Spopovitch and Yamu's mission is accomplished. Spopovitch and Yamu fly away. Gohan is left weakened. As Kibito offers to heal Gohan to full health, the Supreme Kai asks Goku and the others to join him in pursuing the culprits.

Piccolo abandons his fight against Shin. Piccolo learns from Kibito that Shin is actually the Supreme Kai. The Supreme Kai is believed to be even more powerful than the Grand Kai. Videl is fighting against Spopovitch. Videl appears to get the upper hand in her match, but Spopovitch keeps getting up no matter how many times he is knocked down. He eventually fights back. Goku suspects that something is amiss about Spopovitch. Goku realizes that Spopovitch is no longer the same person as in the past and thinks that Videl must abandon the fight. The last time Spopovitch participated in the tournament, he barely lasted 5 seconds in front of Mr. Satan. Something has changed in him. He has acquired new powers. This proves true when he continues fighting even after Videl breaks his neck. Seeing his opponent tired, Spopovitch regains the lead over Videl. Videl attempts to use her flight to regain her strength, but Spopovitch follows her into the air and uses an energy blast against her. As Videl refuses to give up despite the beating she is taking, Goku wonders where Spopovitch got his power from.

While Trunks seems to have the advantage, Goten turns Super Saiyan to free himself from his opponent's grasp when he was not allowed to do so. Trunks takes on a challenge by trying to beat Goten with only his right arm. The latter also becomes a Super Saiyan and sends an energy ball to hit Goten, which lands on a part of the bleachers. The final juniors division match eventually comes to an end, where a sneak attack by Trunks causes Goten to lose by ring out. Trunks wins the battle as well as the juniors division tournament. Trunks will fight Mr. Satan in an exhibition match. Mr. Satan watched the fight between Goten and Trunks. He is reminded of the battle with Cell. Mr. Satan faces a problem because he has to fight against Trunks. After various attempts to try to get out of the fight, Mr. Satan decides to pretend to lose and have Trunks hold back his attack in order to keep up his public appearance. Trunks' weakest punch manages to send Mr. Satan flying out of the ring.

The preliminary rounds begin. The fighters must hit a punching machine to rank their strength. The Dragon Team effortlessly qualifies for the tournament. Vegeta destroys the machine with a single punch. Afterwards, Goku and the others decide to go and watch the tournament of the juniors division.

After Gohan spreads word of the tournament to the others as well as managing to convince Chi-Chi to let him participate himself, Gohan takes a leave of absence from school and begins training with Goten. Gohan is surprised to find that Goten not only possesses great strength, but he is also already capable of transforming into a Super Saiyan even though he has yet to learn how to fly. Videl comes around to have Gohan make good on his promise to teach her how to fly.

The next day, Gohan learns that Chobi, who is the child of Toto the pterodactyl, has been captured by a circus and put on display. In his attempt to rescue Chobi, Gohan is portrayed as a criminal. Videl pursues Gohan as a suspect. When Chobi's parents attack the city in search of their child, Gohan manages to handle the situation and return Chobi to his parents. Videl discovers the truth that Gohan is Great Saiyaman. Videl blackmails Gohan into participating in the 25th World Martial Arts Tournament. As some of the other Z Fighters express interest in the tournament, Goku calls out from the Other World and says he will return to Earth for a single day to participate.

Soon after, Gohan saves the passengers of a plane about to crash and extinguished a fire that caught fire in a building in the city by destroying the water container. On his way to school, Gohan is chased by Videl in her helicopter, who is trying to find out who is hiding under the mask of Great Saiyaman. Gohan escapes by placing Videl's helicopter on the roof of a building. Both of them arrive to school late, which leads Videl to be even more suspicious of Gohan. Later, kidnappers from the Red Shark gang take the mayor of Satan City hostage. The police warn Videl of the situation, so she responds by confronting the leader of the gang. Meanwhile, Gohan, growing impatient of class since he would rather assist Videl as The Great Saiyaman, starts aggressively tapping his foot, triggering an earthquake. He slid out of class during the confusion and arrives to the scene of the crime as the Great Saiyaman. Gohan saves the mayor of the city while stopping the attempts of the rest of the gang. Videl learns that Gohan was out of school at the same time. Videl is led to believe that Gohan and Great Saiyaman could really be the same person.

The World Martial Arts Tournament begins, and Goku battles the mysterious fighter called Uub.

It has been ten years since Buu was defeated. Goku, Goten, Vegeta and Trunks enter the World Martial Arts Tournament, where they also meet up with old friends and family.

Goku struggles to destroy Kid Buu, who pushes back against the Spirit Bomb.

Vegeta attempts to convince the people of Earth to give their energy for the Spirit Bomb. Meanwhile, Fat Majin Buu has lost all his energy, and Kid Buu begins another onslaught onto Vegeta, forcing him to fight again.

The people of Earth are wished back to life, and Goku begins creating the Spirit Bomb in a final attempt to destroy Buu.

Fat Majin Buu enters the fight and saves Vegeta from death. Meanwhile, Dende makes two wishes using the Namekian Dragon Balls.

Vegeta steps in to fight Kid Buu, while an exhausted Goku attempts to regather his power.

Goku powers up to Super Saiyan 3 in an attempt to destroy Buu once and for all.

Goku fights Kid Buu on the Sacred World of the Kais.

Vegeta and Goku save their friends and family, causing Super Buu to regress into his original, child-like form.

Still absorbed inside his body, Goku and Vegeta fight the beings manifesting from Buu's mind.

Super Buu absorbs Vegito, who had planned for the turn of events in order to save his friends and family.

Vegito continues to fight Super Buu, who is clearly outmatched by the Saiyan warrior.

The ultimate fusion of Goku and Vegeta, Vegito fights Super Buu.

Desperate to match Super Buu's power, Goku convinces Vegeta to fuse with him using the Potara earrings.

Super Buu's plan of absorbing Piccolo and Gotenks succeeds, and begins to outmatch Gohan.

Super Buu devises a plan to gain the upper hand against Gohan.

With newfound powers unlocked by Old Kai, Gohan fights Super Buu.

As victory seems near for Super Buu, who overpowers a weakened Gotenks, Gohan arrives just in time.

Gotenks and Super Buu continue their battle.

Super Buu manages to escape the Hyperbolic Time Chamber, causing Gotenks to finally unleashes his trump card.

Gotenks and Super Buu continue to fight, with Gotenks unleashing his special move called the Super Ghost Kamikaze Attack.

Hoping to avenge their loved ones, Gotenks fights Super Buu in the Hyperbolic Time Chamber.

Piccolo tries to buy some time after Super Buu unleashes a powerful attack which kills most of the lives on Earth.

Majin Buu attempts to fight against the Evil Buu, who is revealed to be much more powerful.

After witnessing Hercule getting shot, the evil escapes from Majin Buu's body, releasing a tall, gray and emaciated version of Majin Buu.

Old Kai begins the process of unlocking Gohan's true potential. Meanwhile, Majin Buu befriends a dog and Gotenks practices becoming a Super Saiyan.

Gotenks arrive to fight against Majin Buu.

Finally mastering the Fusion Dance, Gotenks goes out on a search for Majin Buu, despite Piccolo's protest. Meanwhile, Old Kai reveals he has the ability to unlock a warrior's true potential.

Goku arrives in the Sacred World of the Kais, where Gohan has been training with the Z-Sword.

Goku returns to the afterlife, leaving Piccolo to continue training Goten and Trunks.

Due to his energy being drained from transforming into a Super Saiyan 3, Goku does not have much time left on Earth. He wastes no time, teaching Goten and Trunks the final key component to mastering the fusion technique.

Goku, who has transformed into a Super Saiyan 3 for the first time, fights Majin Buu.

Babidi and Majin Buu plan to destroy West City, however Goku confronts them, hoping to buy some time. Meanwhile, Trunks is on a mission to retrieve the Dragon Radar from West City, which will be destroyed if Buu gets there first.

As Majin Buu lays waste to another city, Goten and Trunks contact Babidi and inform him that they will soon be strong enough to fight Buu. They continue their fusion training.

Supreme Kai reveals his plan to teach Gohan the art of mastering the legendary Z-Sword in order to defeat Majin Buu. Meanwhile, Goku teaches the fusion technique to Goten and Trunks.

Kabito and Supreme Kai finally find Gohan, and Babidi makes a worldwide announcement.

Understanding that he cannot defeat Majin Buu, Goku teaches Goten and Trunks the fusion technique.

Goku learns of Vegeta's sacrifice, which ultimately failed to defeat Majin Buu. Meanwhile, a weakened Supreme Kai searches for Gohan, whose fate is still unknown.

A desperate Vegeta sacrifices himself by self-destructing into a massive explosion, in an attempt to destroy Majin Buu once and for all.

Majin Vegeta fights Majin Buu, and is shocked by Buu's regenerative abilities.

Majin Buu easily defeats Gohan and Supreme Kai. Fearing that Majin Buu cannot be controlled, Dabura attacks the powerful being.

As Majin Buu is revived, Gohan and Supreme Kai try to flee from this powerful foe.

As the fight between Goku and Majin Vegeta escalates, Gohan attempts to stop Majin Buu from reaching full power.

While the fight between Goku and Majin Vegeta intensifies, Gohan and Supreme Kai attempt to stop Majin Buu from being revived.

The fight between Goku and Majin Vegeta begins.

As the battle between Dabura and Gohan continues, Babidi plots to sway Vegeta to his side using magic.

Android 18 makes a deal with Hercule to let him win the match in exchange for the prize money. Meanwhile, Gohan fights Dabura.

Android 18 continues fighting the mysterious Mighty Mask.

After Goku defeats Yakon, Dabura prepares to fight the Saiyans himself. Meanwhile, a battle royal is held between the remaining contestants of the tournament.

After Vegeta effortlessly defeats Pui Pui, Goku prepares to fight Yakon.

Goku, Vegeta, Gohan and Supreme Kai chase after Dabura into the spaceship, where they are confronted by one of Babidi's minions, Pui Pui.

Goku and the others arrive at the site of a buried spaceship and watch as Spopovitch and Yamu deliver Gohan's energy to the evil wizard Babidi and his partner, Dabura.

After Videl is defeated by Spopovitch, Gohan prepares to fight against Kabito.

Piccolo goes up against the mysterious being called Shin.

During an intermission, as Goku and the others get something to eat, they are encountered by two mysterious participants.

Goku, Vegeta and other others spectate the tournament, while Gohan and Videl wait to take their preliminary test.

On the day of the tournament, Goku is allowed to return to Earth for a 24 hour visit as granted by Fortune Teller Baba.

Gohan teaches Videl the basics of learning to control her energy.

Gohan creates an alias called the "Great Saiyaman", allowing him to stop criminals while also concealing his true identity.

Seven years after the battle with Cell, Gohan is now a high school student attending Orange Star High School.