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!

Goku, Supreme Kai, and Glorio head out to the "Demon Realm" first. Their plane travels through space and a mysterious dimension. They arrive at the entrance to the Demon Realm, the "Third Demon World"!

After encountering the Gendarmerie, the wardens of the Demon Realm, the four are forced to camp in a cave where they encounter further trouble! The enigmatic Glorio unleashes lightning magic against Goku to resolve the situation!