In the Other World, a careless teenage ogre in charge of the soul cleansing machine falls asleep, causing a catastrophic overflow of concentrated evil energy. The machine explodes, transforming the innocent worker into Janemba, a towering, reality-warping demon of immense power. Janemba’s sheer malice instantly shatters the barriers between dimensions, wreaking havoc in the afterlife and causing historical villains from Hell to invade Earth en masse.Goku and Pikkon are left trapped by the anomaly in King Yemma’s sealed office, leaving Pikkon to figure out a clever way to melt the crystal barrier isolating them. Meanwhile, Gohan, Videl, Goten, and Trunks return to Earth to fend off the sudden uprising of resurrected tyrants, famously sending Hitler and his Nazi army packing back to the nether regions.Back on Earth, Goten and Trunks quickly fuse into Super Saiyan Gotenks and use their ghostly kamikaze attack to seal the rift between worlds, while Gohan deals with the lingering paranormal threats. In the Other World, Goku finally breaks free and confronts Janemba, who initially poses a formidable challenge with his reality-bending tricks and portal-creation. Recognizing the dire threat, Goku transforms into a Super Saiyan 3, unleashing a brutal flurry of martial arts that ultimately forces Janemba to undergo a terrifying
metamorphosis into a sleek, smaller, and vastly more lethal warrior. This new form easily overpowers Goku, leaving the legendary Saiyan bruised and outmatched.Simultaneously, Vegeta is wandering through the spirit world when he encounters the demonic energy. Drawn to the commotion, he arrives just in time to rescue Goku from Janemba’s onslaught. Prideful as ever, Vegeta refuses to team up initially, but soon realizes that brute force alone is utterly useless against the demon's reality-warping abilities.Realizing their only hope lies in cooperation, Goku convinces a reluctant Vegeta to perform the ancient Metamoran Fusion dance. After a minor comedic misstep where Vegeta botches the finger extension, they successfully merge on the second attempt into
the ultimate warrior: Gogeta. Radiating supreme confidence and staggering power, Gogeta wastes no time. He effortlessly unleashes the Stardust Breaker—a brilliant, multicolored sphere of energy that completely obliterates the inner evil consuming Janemba without harming the innocent ogre trapped inside.With the malevolent entity destroyed, reality snaps back into its proper place. The dimensional rifts seal themselves, the resurrected villains vanish back to Hell, and the universe is saved. Though Vegeta is typically grumpy about fusing with his eternal rival, he and Goku part ways peacefully, leaving the Other World to slowly pick up the pieces after one of its most chaotic and near-fatal disasters in cosmic history.