A powerful force has just destroyed the South Galaxy, and King Kai, fears that our galaxy will be the next to go.

Spring has begun, and while the others go off and have fun, taking in a traditional view of the cherry blossoms, Goku is held in Chi Chi's grasp. She drags him along to a parent interview, which will test their worth, and be a deciding factor weither Gohan is accepted to the school. Goku is, as expected uncomfortable. Chi Chi insists he be proper, having him wear a business suit, and lie about his hobbies (he wants to say fighting tough opponents, but she tells him to say reading and sports!).

While the two are in their little lying contest, their friends are enjoying the peaceful blossoms. Krillin is screeching out some karaoke, which is driving Vegeta insane, when a large circular spaceship descends from above. It belongs to Paragus, yet another Saiyan left after the destruction of planet Vegeta, along with his own army. Paragus persuades Vegeta, as the last of the saiyan royalty, to come with him to his new planet Vegeta, and help rebuild the fallen saiyan Empire. Vegeta decides against it, but Paragus speaks up about the Legendary Super Saiyan. He tells Vegeta that he is the only one who has the power to defeat such a warrior... one who has already destroyed the South Galaxy... To this Vegeta agrees, and boards the ship, along with Roshi, Trunks, Oolong, Gohan, and Krillin.

Somewhere between all of this, King Kai has contacted Goku telepathically. He tells him of the Saiyan power he felt in the South Galaxy, and that he'll be in the North Galaxy soon. Goku then teleports to King Kai's planet, attempts to detect the ki of the warrior, teleports that the suspected location, only to find him gone. An incredible ki is still present, though.

The others have since arrived at the new Planet Vegeta. Upon reaching a group of people celebrating Vegeta's return, Paragus introduces him to his son, Brolli, a slim, tall, and quiet young man. A soldier informs Vegeta that the legendary Saiyan showed up on planet Tonosama. This surprises Vegeta, and he quickly enlists Brolli to help him take care of him. Trunks asks his father to first gather more information on this dangerous situation, but Vegeta refuses, and makes his way to the site.

Trunks, Gohan, and Krillin follow along, and Krillin begins to doubt the existence of such a warrior. Trunks agrees, but he reassures that his father believes it fully. They discover that the planet is mostly in ruin, with little or no life left on its surface. Gohan can't quite understand why Paragus would want to rebuild the Saiyan race on such an inadequate planet. Suddenly, Krillin sees a giant dome shaped light of some kind over the horizon. The group finds that it's actually energy being pumped from the core of the planet and sent to the palace, so it can support life. This task is being performed by a race of aliens, taken from their own home after the Saiyans destroyed their own home. They're being treated as slaves, malnourished and overworked, and they see the Saiyan as the demons of the universe. A soldier jumps down and sees the small child who had divulged this information to our heroes, and begins to hit him with a whip for slacking off. Gohan acts quickly and busts the soldier in the face, smashing right through his helmet he whistles for help, which comes and encircles Gohan. Krillin just kind of laughs and tells the squadron not to be messing with them, because of their strength. The goons quickly back off. Krillin's ego gets bigger, and he starts punching and kicking at the air, just as Goku materializes in front of his fist. He catches a hard right to the jaw, which knocks him down. Krillin asks him what he's doing here, and he tells them that he was simply following the ki of the legendary Saiyan. Krillin tells Goku about the whole Vegeta thing, and suddenly Paragus appears, welcoming 'Kakaroto' to the planet. He knows that he is Bardock's son, and asks him to stay awhile and have a meal. Goku comes to the conclusion that the ki he felt was certainly not that of Paragus', and has his dinner. The aliens are having a meal of their own, along with Trunks, Krillin, and Gohan. They ask if it was Paragus that attacked their planet, but are met with a resounding 'no'. Trunks sensed very little power from Brolli, so he decides that the legendary Saiyan must be far off somewhere... Paragus is in an observatory, high above his city, strangely asking that a comet known as Kumorie come destroy his planet. Vegeta and Brolli return unsuccessfully from their trip, and are met by Goku who is hanging around the castle. Vegeta tell Goku not to interfere with his plans to kill the legendary Super Saiyan and walks off. Brolli then stares at Goku with bitter rage, clenching his fist, and creating a huge aura of energy around the two. Paragus sees this and attempts to calm Brolli using some strange contraption on his hand. Roshi and Oolong round the corner, and ask Paragus to prepare a ship for their departure, as they've seen enough of the planet. Brolli then calms down, and his aura fades.

Later that night, Paragus is having his hand device checked by a scientist. He says it isn't broken, and perhaps Brolli is just becoming too much for it to control. Paragus walks out of the lab, and worries that Goku is the cause of him being unable to control Brolli with his instrument. He has flashbacks dating back to when Brolli was an adolescent, a Super Saiyan who was quickly destroying a city with ki blasts. He talks about how Brolli is a true breed of Saiyan. He was born with incredible power and as he grew up, it became so violent and threatening that it scared him. He had a scientist to create a tool that would work in conjunction with a remote device to control Brolli's power. It consisted of a golden headband, and a matching gauntlet remote, which in turn gave him the power to rule the universe with Brolli under his command. He figures that if the tool is still working, then it means that his meeting with Goku made him unable to be harnessed. Paragus then remembers that Goku and Brolli were born on the same day...

the movie then cuts to the hospital, where baby Brolli and Goku are lying in their cribs. Goku is bawling his eyes out. Two doctors are discussing how incredible it is that Brolli was born with a fighting power of 10,000, while Bardock's son, Kakaroto was only born with a meager level of 2. Kakarot's crying was making Brolli cry as well, so one of the doctors suggests that though his combat level is low, his fighting spirit is incredibly high.

Paragus looks in on Brolli sitting in a chair, filled with rage and shaking like a madman. Paragus damns Goku, and realizes that if he can't control Brolli, the universe will be destroyed. Brolli raises his energy and screams out "Kakaroto!!!"

All of our heroes are in bed, asleep, when Brolli bursts in and tears up the place, looking to kill Goku. He gets him outside, and over a lake, just as Paragus hears the commotion and grabs his wrist remote. Goku finds it interesting that Brolli can hide his power like the Z fighters. Brolli rushes at Goku and gets kicked in the face, leaving a trail of blood running from his mouth. Brolli licks it up, and smiles. Goku's attacks are beginning to have no effect on him, and eventually Brolli begins to power up further, beefing up his muscles, and leading Goku to sense the same ki he had felt earlier. Paragus arrives, and attempts to calm Brolli down. It works, and the father and son duo fly home. Goku has found the identity of the legendary Super Saiyan. We then see a brief shot of the dreaded comet coming closer to the planet...

The next morning. Vegeta and Brolli are making their way to the spaceship, much to the dismay of Paragus. He wants to keep Vegeta on the planet until the comet hits. Brolli begins to go insane again, as he hears Goku's voice coming from within the spaceship. He tells Vegeta that he doesn't need to go anywhere to find the legendary super Saiyan, since he's with them now. Goku instructs Paragus to confess to Vegeta about Brolli's status as the legendary super Saiyan. Paragus denies this fact, and asks Vegeta to return to the palace. Trunks then shows up, loudly declaring that Paragus is lying about everything. He informs them of the alien race he has enslaved to make the planet what it has become. While they ascend the hill towards the fighters, one of the alien children sees Brolli and announces him as the one who attacked their home planet. Vegeta is outraged at this trickery, and Paragus finally confesses. His true location to rebuild the Saiyan Empire was on Earth where resources are abundant, but he feared Vegeta would be in his way. That's why he designed a mock kingdom on a planet, with a comet fixed impact. By luring Vegeta there, and escaping the planet just before collision, Paragus would have no competition in the universe, and would be free to rule it with Brolli.

Brolli's anger consumes him, so he goes SSJ and walks slowly towards Goku. Vegeta immediately transforms as well, and tries to defeat Brolli with absolutely no success. Brolli's rage envelops him to such an extent that he is finally able to transform into a true super Saiyan and his golden headband shatters. His insane mind is now free. Vegeta is completely astonished at this occurrence, and he is reduced to a statuesque state of frightful awe. Gohan jumps in and tries to help his dad in the fight, but is quickly injured by simply coming into contact with the legendary warrior. As Trunks swoops in to help, Vegeta admits to himself that there will be no escape from this monster... Brolli will kill them all.

Paragus begins to speak indirectly to Vegeta. He regrets that his plan has failed him. He recollects on his hate for Vegeta's father, who saw Brolli's great power for what it actually was... a great threat. He wanted the baby killed off, and when Paragus Tried to persuade him against it, he was killed and thrown off into the dumps along with his son, who had been stabbed to death. But... they didn't die. Just as Freeza sent his death ball to destroy the original planet Vegeta, Brolli's latent power sprung to life and resurrected the both of them, and transported them into space, in a strange ball of energy. Since then, Paragus only lived for revenge, if not on King Vegeta, then on his son.

So begins the fight. They're not having much luck. Brolli's size doesn't decrease his speed in the slightest, and his brute strength is overwhelming. Krillin, Oolong, Roshi, and the alien slaves show up, and are attempting to escape the doomed planet. Brolli notices the aliens, and reminds them of the times they looked up at their home planet and wondered when they could return. He fires a blast at the aliens, but it ricochets off of the ground, and flies backwards. He wasn't aiming for them at all! It soars higher and higher, then collides with their planet, completely obliterating it. The monster simply laughs at this event, and the slaves are forced to move along off of the battlefield with Krillin and the others.

The battle rages. Trunks keeps getting rammed violently in to walls and such, Gohan gets knocked out and hung on a rod, and Goku generally can't do much damage do the big warrior. Though he does get off a great line. After pummeling Goku with ki blasts, only to have Goku to walk out still standing, Brolli asks "don't you ever give up?" To which Goku responds, "Heh, I never learned how."

Brolli discovers that his ki is growing in strength. He's having real trouble controlling his own actions anymore, and what was left of his mind seems to be deteriorating quickly. He uncontrollably sends a flurry of ki blasts in all directions destroying much of the planet. He finally regains control of himself and senses something from Gohan. He throws a ball of energy at him, which is deflected by the one and only, Piccolo! Brolli decides that he's just another bug waiting to be squashed. Piccolo calls him a monster and tells him to do his best, but Brolli doesn't like to refer to himself as a monster, "monster? No, I'm the devil."

Piccolo gives each of the fallen heroes a senzu, and explains to Goku that the reason he knew their location was because he heard King Kai's and Goku's conversing earlier. He came as fast as he could on a spaceship. He also admits that he has never felt a ki as strong as Brolli's before. Meanwhile, Paragus is surveying the ever-approaching comet, while Krillin, Oolong, and Roshi have departed. Piccolo grabs Vegeta, and tries to get him to help them fight, but Vegeta is scared of Brolli's power. Piccolo is ashamed that a prince could be so cowardly, so he drops him to the ground, and flies back to the battlefield. Lying in the rubble, Vegeta asks himself the reason they continue to fight, though they know they can't win. He finally renounces his fear, and joins his allies on the field, despite the fact that it probably won't change things.

Paragus is making his way to his space pod. Only a few hours remain until the comet will make contact. He decides that since he no longer has control over Brolli, he will just let him die along with the planet. But just before Paragus can launch off, Brolli shows up and asks him where he's going. He sees that his father has only been using him for all these years, so he takes the ship, crushes it with his father still inside, and throws it into the comet. Though this may seem harsh, Paragus mentions that it is the cursed destiny of the Saiyan for the son to kill the father. It would seem that Brolli has won. Everyone is out of the game, and he's free to move on. But Goku is one that will never say die. He walks confidently towards Brolli, his body mangled, his power spent, but his spirit still intact. Piccolo utters that everyone give Goku what power they still have left. Vegeta is the only one to refuse. Goku still doesn't have what it takes to kill the monster. Brolli begins to stomp repeatedly on Goku's chest, resulting in massive damage. All the while the comet is getting closer and closer. Goku is still taking punishment; he just can't do it without Vegeta's energy. Brolli is getting incredibly pissed off at Goku, and how he just won't give up, though his pain is intense. Finally, Vegeta abandons his status, and begins to give him his power. Just as Brolli is about to deliver the final blow, Goku catches his fist, and lets off a supercharge of energy, that bewilders Brolli, and makes him back off a bit. One by one, each of the warriors tap out of their energy, and leave it all up to Goku. The comet is within the atmosphere of the planet, and the ground is beginning to break apart, both warriors charge at each other, at the same speed. Brolli gets above Goku, and is ready to slam Goku from above, just as Goku uppercuts him into the gut, twisting his fist as he goes. Brolli flashes back to when they were babies in the hospital, and Goku's crying was making him cry as well, then it was all over. Goku's punch hit him so hard that it burst right through his stomach, and made him explode in a fiery array of light. Goku fell back and shouted "WE BEAT HIM!" just as the planet was disintegrated by the comet.

Goku teleports all his friends and the slaves to the ship being flown by Krillin, Roshi, and Oolong. Goku gives the camera a peace sign, and teleports home with Gohan. There they meet a disgruntled Chi Chi who complains to Goku that they've been gone so long that Spring Break is over. To this Goku replies, "My hobbies are reading and sports!" Chi Chi falls over, and Goku and Gohan rush to check on her. The universe is safe once again.