Trunks travels back from the future to hone his skills alongside Goku and Vegeta, but he vanishes unexpectedly. Suddenly, the enigmatic Fu appears, revealing that Trunks has been trapped on the Prison Planet, a strange facility located somewhere in the universes. The team embarks on a quest to gather the dragon balls to liberate Trunks, but they face relentless battles along the way. Can Goku and his allies manage to save Trunks and break free from the Prison Planet?