Dragon Ball Z: Arrival

The Salyans are a race of alien warriors who crave destruction. They have sent their might warrior, Raditz, to the Earth to search for his younger brother, Kakarot, and to finish the job his brother neglected - to destroy all traces of human life on the planet!

Raditz confronts Goku, one of the Earth's greatest defenders, and shocks everyone by revealing that Goku is really Kakrot with amnesia! Raditz commands Goku to accept his heritage and attack the Earth. When Goku refuses, Raditz kidnaps Goku's son Gohan and commands Goku to destroy 100 earthlings by the next morning to save his son's life. Still reeling from the shock, Goku suddenly finds help from an unlikely source - his arch enemy Piccolo! Despite their differences, they both realize that they must team up if they want to have a chance against Raditz. However, once their battle against the Salyan has begun, it becomes obvious that, even together, they are not powerful enough to challenge Raditz! Now will they make up the difference? What sacrifices will have to be made to protect the Earth?