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!

With the mighty Kaio-ken amplifying his strength, Goku fights Vegeta in a desperate battle to save the world, only to find that the elite Saiyan warrior is even stronger than his own techniques! Goku calls on the Genki-dama, the "spirit ball," drawing power from every living thing around him. But alone, even Goku is not enough. The last worn-out survivors, Gohan, Kuririn and Yajirobe, rush back into the fray to try and stop the unbeatable Vegeta from destroying the planet Earth itself!