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"!

Goku and his companions arrive at the mystic Second Demon World where a giant ocean spreads as far as the eye can see! The party is amazed at the new world but is immediately attacked by Gendarmerie that have been sent by Gomah!

Having regrouped with Vegeta and the others, Goku and his companions arrive at a planet that seems familiar. As they move to head out, a suspicious shadow approaches! It's the Legendary Namek who remained alone in the Demon Realm!