Dragonball: Evolution movie

The story begins with a young humanoid boy named Goku, who discovers that he was sent to Earth to blend in and destroy our population but instead elects to protect it from an oncoming alien onslaught bent on dominating the universe and controlling the mystical objects. He seeks out upon his adoptive grandfather Grandpa Gohans dying request to find the great Master Roshi and gather all seven Dragon Balls. Of which he has one, in order to prevent the evil Lord Piccolo from succeeding in his desire to use the Dragon Balls to take over the world. And Gokus quest is to obtain the mystical Dragonballs before Piccolo does.