As the saiyan planet is about to be destroyed he sends his two young sons Goku and Raditz to the planet earth,however as Goku gets deflected by a meteor and bounced to another planet while raditz heads to earth.Raditz's space pod crashes right on earth and opens,as soon as it opens Raditz falls and hits his head on a rock causing him to get knockedout.
But as for Goku,he lands on the planet where vegeta has been living on since the destruction of their planet...
Raditz is rescued by an old man and taken care of by the man.The man tells Raditz "my name is Grandpa Gohan what is your name?" instead of Raditz trying to take over the planet he only remembers his name and tells Grandpa Gohan"my name is Raditz"...
Grandpa Gohan takes care of Raditz but sadly he soon passes away.Raditz meets bulma and the story is about to unfold.