Five years after his victory in the World Martial Arts tournament, Gokuu is living a peaceful life with his wife and son. However, this tranquility is disrupted by the arrival of a mysterious enemy named Raditz, who claims to be Gokuu's long-lost brother. Raditz reveals that Gokuu is a descendant of the Saiyan race, once powerful but now virtually extinct, whose homeworld was annihilated. When Gokuu was sent to Earth as a baby, his sole purpose was to conquer and destroy the planet; but after suffering amnesia from a head injury, his violent and savage nature changed, and he was raised as a kind and well-mannered boy, now fighting to protect others. Following his failed attempt to forcibly recruit Gokuu as an ally, Raditz warns Gokuu's friends of a new threat rapidly approaching Earth—one that could plunge the planet into an intergalactic conflict and cause the heavens themselves to shake. A war will soon be fought over the seven mystical Dragon Balls, magic objects that can grant any wish. Only the strongest will survive.