With no new battles to fight, Goku has been living a quiet life in the countryside with his wife Chi-Chi...and their son Gohan! While Goku makes plans to spend a happy day with friends on Master Roshi's island, a powerful new threat is on its way to Earth. And the arrival of this sinister alien could spell disaster for Goku and his friends!

Goku and Gohan attend a reunion on Master Roshi's island, where Goku introduces his son to all of his old friends. The smiles quickly fade, however, as an unexpected visitor lands on the island, and for Goku the day becomes a reunion of a different kind. A powerful alien has arrived. It's Raditz: Goku's evil older brother!

Raditz has kidnapped Gohan! And unless Goku agrees to forsake his friends and the people of Earth by joining the sinister Saiyan, he may never see his son again! All hope is not lost, however, as a second uninvited guest arrives on the island - and Goku forges an unlikely alliance!