Son Goku Jr. is the great-great-great-great-grandson of the legendary warrior Son Goku. However, unlike his predecessor he's not a brave fighter. He's constantly picked on by school bullies, his grandmother Pan sees this and she's worried, but even though Goku Jr. is not a strong and powerful Saiyan, he has a kind heart, and Pan loves him. When Pan gets sick Goku Jr. realizes he must do something if he doesn't want to lose Pan. Then he will remember about the legends of the Dragon Balls. It was told they granted a wish to the bearer, Goku Jr. needs a magical wish more than ever.
Trunks returns from the future to train with Goku and Vegeta. However, it disappears without warning. Then the mysterious Fu bursts in, telling them that Trunks has been imprisoned in the Prison Planet, a mysterious complex in an unknown place in the universes. The group seeks the dragon balls to free Trunks, but an endless battle awaits them! Will Goku and the others rescue Trunks and escape the Prison Planet?