After a cleaning mishap, a custodian transforms into Janemba, a plump, yellow demon wreaking havoc in the afterlife. Gokuu Son competes in martial arts competitions in the undead realm after his death fighting Cell. Janemba's chaos draws in Gokuu and fighter Pikkon, causing them to plot a plan against the colossal beast. Following a fierce battle, Janemba transforms again into a sword-wielding foe, shedding weight and becoming more formidable than Gokuu's previous foes. With the aid of his former enemy Vegeta, Gokuu must prevent Janemba from destabilizing the universe.