A giant castle in a mysterious world. Two shady Majin, Gomah and Degesu, watch a monitor. The monitor shows Goku and the others having a fierce battle against Majin Buu. Gomah and Degesu head to Earth to execute a certain conspiracy.

Goku and his friends have been turned small due to Gomah's scheme. They begin preparing to go to the demon world. Goku collects his Nyoibo and looks forward to a new adventure. Then the mysterious young Majin Glorio appears!