After years of searching, Emperor Pilaf finally gets his hands on the Black Star Dragon Balls, which are rumored to be twice as powerful as Earth's standard ones. Just as Pilaf is about to wish for world domination, Gokuu Son interrupts him. Consequently, Pilaf botches his wish and inadvertently reverts Gokuu to a child. Once the wish is granted, the Black Star Dragon Balls scatter across the galaxy. However, Gokuu learns that they will cause Earth to explode unless all of them are retrieved within a year. Teaming up with his granddaughter Pan and a young adult Trunks, Gokuu embarks on a journey through the universe to locate the Black Star Dragon Balls and save his planet from destruction.