A seed of the Tree of Might has been planted on Earth by a group of space pirates. Once rooted, the Tree of Might will devour all life energy, leaving the planet a deserted land where no living thing can survive. Goku and his friends try to destroy the tree but find their power is not enough. Suddenly, they are attacked by the evil space pirates, and Gohan is captured by Turles, the evil leader of the group and a Saiyan! Turles powers up by eating a fruit of the tree and challenges Goku. Can Goku save Gohan and the planet Earth from Turles!?