Son Goku is the greatest hero on Earth. Five years after defeating the demon king Piccolo, he's grown up and has a family. But what is the real reason for Goku's incredible strength? A visitor from outer space arrives bearing terrible news--Goku is an alien, and the visitor, Raditz, is Goku's brother! When Raditz turns out to be a ruthless killer, Goku must fight his incredibly strong brother to save his family and the entire human race. A surprising alliance may be Earth's last hope: Goku will team up with his old enemy Piccolo to save the world!

While Goku races toward Earth along the million-kilometer Serpent Road, the world's mightiest martial artists make their last stand against alien invaders determined to wipe out the human race! Piccolo, Gohan, Kuririn, Tenshinhan and Chaozu struggle five-to-one against Nappa, only to find their opponent's power is greater than they ever dreamed. Their last chance is Goku...but can he get there in time?