Vegeta has been possessed by Babidi, the pint-sized, ugly little magician. He is now Majin Vegeta, with an M embedded onto his forehead to indicate his new status as one of Babidi's servants, or is he? Babidi takes the liberty of teleporting the whole gang (Gohan, Goku, Kaioshin, and Vegeta) to the Tenkaichi Budoukai arena to fight it out there instead of at the spaceship. The crowd is surprised at the sudden appearance and Mr. Satan is even more shocked and afraid. He points at Vegeta and tries to convince him not to kill people, but his pleas obviously fall on deaf ears. Majin Vegeta asks Kakarot to fight him. When Goku hesitates, Vegeta sticks out a hand and fires an enormous blast, taking out another section of the arena and killing more people. Goku is getting angry and Gohan tells Vegeta to stop the madness. Vegeta swings his left hand and the impact blows Gohan a few feet away. Goku decides that the fight with Vegeta is inevitable and so transforms into SSJ. Goku asks Vegeta if he deliberately allowed Babidi to charm him just so that he would have an excuse to fight him. Kaioshin interjects, saying that allowing Babidi to do that just to be able to fight Goku was completely stupid. Vegeta gets pissed at this and instantly releases ki in every direction, saying aloud how he hated Kakarot for defeating and even saving him in the past. Goku then tells Babidi by shouting out (Babidi can hear whoever's talking within the place shown in his magic sphere) that he wants to fight Vegeta, but in a place without people. They are teleported to a desert-like environment with some rocky hills and mountains here and there.

Gohan and Kaioshin (who has decided to leave Goku and Vegeta alone) decide to go inside Babidi's spaceship to eventually reach the bottommost chamber and prevent Buu from hatching. Babidi instantly realizes their plan and tells Vegeta to kill the interlopers. Vegeta, after struggling and painfully holding his throbbing head periodically, refuses and enunciates that his only desire to fight Kakarot, nothing else. To get this through Babidi's head, he and reaffirms his status as a proud Saiya-jin prince and powers up, causing the surrounding mountains to collapse (very cool). Gohan and Kaioshin enter the ship unobstructed, and the second major fight between Goku and Vegeta is about to begin. Goku doesn't want to allow Vegeta to damage him, because doing so would add that amount of "damage energy" to revive Buu. Accordingly, he goes SSJ2. Vegeta comments on his new skill and power, but then he also blasts into a seemingly equally powerful SSJ2 form. Goku realizes that he has no choice but to fight Vegeta despite the fact that the fight would not be a short one.

As Goku and Vegeta fight furiously and match each other's attacks almost every time (it's undoubted that their power levels are extremely close), Gohan and Kaioshin are going down to where Babidi and Darbura are. After killing some weak henchmen in a few seconds, the two proceed on. Goku and Vegeta are still enjoying their time fighting at full power, without anything holding them back. Gohan and Kaioshin finally reach the spaceship, but Babidi, with his powerful magic, and Darbura are standing in front of Buu's egg. Suddenly, the meter on the egg indicates that Buu is about to hatch, even after such a short time of fighting between Goku and Vegeta. The egg is brought to sea level, so that the spaceship does not get destroyed. When Buu does come out, he is shown to be a fat ball of pink lard with an an antenna on the top of his head. Buu is rather child-like, as is seen when he sticks his tongue out at Babidi, refusing to obey his orders (until Babidi reminds him of his power to imprison Buu in the egg again).

Buu decides to show-off his power first on Darbura, who instantly blasts off towards Buu and envelopes him in a flurry of punches and kicks. Buu seems to be incapable of fighting back, but he remains unhurt even when Darbura used his signature attack (firing continuous energy balls from the sky) on him. Darbura decides to finish Buu with his saliva. He spits at Buu with two tries, stoning a lizard at the first but missing both times. Buu uses his antenna to turn Darbura into a life-sized chocolate cookie. As Gohan and Kaioshin watch in terror, Darbura falls to Buu's hand and is eaten. Gohan and Kaioshin decide to make a run for it, but Buu catches up to them with no effort at all. Gohan is knocked down to the ground immediately, leaving only Kaioshin to face Buu. After some unsuccessful attempts to blow back Buu, Buu fires a large pink blast at him. Before it impacts however, Gohan flies towards the two and covers Kaioshin. Gohan is powerless (see what you get for not training for 7 years) as he gets blown away with the ki blast a few miles away. Kaioshin uses telepathy to knock the blast off course, but Gohan is down unconscious for the moment. Kaioshin is then beaten up and sat upon by Buu (ouch), rendering him almost immobile. Before he gets killed, however, Babidi's spaceship explodes.

Majin Vegeta emerges from the rubble, greeting Babidi, who is mad as hell at Vegeta for returning from the fight with Goku and blowing up his only mode of transportation (Vegeta had managed to knock down Goku after tricking him to think that he, too, wanted to postpone the fight to help the others battle the revived Buu. As Goku reached for some Senzu beans to restore both of their energy levels, Vegeta took the liberty of knocking Goku unconscious and flying off with the rest of the Senzus to fight Buu. However it is evident that he did so to avoid Goku getting killed as well. Instead, he decides to take responsibility for his actions (for the first time probably) in allowing Buu to be reborn by hopefully killing him). After reminiscing a bit about all the past times when Goku had surpassed him, Vegeta powers up and proclaims that he intends to go to hell along with Buu and Babidi. In the ensuing beat-up, Vegeta engulfs Buu with punches and kicks with amazing speed and even blasts a hole in Buu's stomach with a yellow blast. Buu seems to be down again but instantly regenerates and is good as new.

Buu then knocks down Vegeta, ripping off a part of his body to tie him up. Trunks and Goten, who have been watching the fight all along, decide to help Vegeta and turn into SSJ mode. They free Vegeta from the entanglement, but Vegeta tells them not to join in on the fight. After hugging Trunks (he never hugged his son before) in a rather emotional scene, he knocks him out, and soon after, Goten as well. He instructs Piccolo to take care of the two when he's gone. Following this is another emotional scene where Vegeta realizes that he'll never see Kakarot after dying because he would go to hell for all the wrongs he committed in the past. He tells Piccolo to go as he powers up again for the last time. Swirls of golden ki go about in every which direction surrounding the reformed Saiyajin prince. In an attack that uses his own life energy, Vegeta releases an explosion 1 mile in diameter, taking out everything within that range. Buu is blown to pieces and Vegeta is turned into stone after when the dust finally settles. The once proud Prince drops frozen onto the ground below and breaks into several parts. After telling Krillin to bring the two kids back to Kami's Skypalace for revival, Piccolo goes to investigate the scene. He feels somewhat sorry about Vegeta being gone, but is also relieved that Buu has been eradicated, or has he? Piccolo hears a sound a short distance away and sees Buu's minuscule body parts coming together to reform into the original Fat Buu. He can't believe his eyes and flees the scene before Buu is back completely.