Fast at Frieza order, they send a baby Saiyan to Earth, hopefully with the help of a few full moon Earth would be destroyed. And the planet would be sold for a worthy prices. 

     The space-pod  has crash on Earth at the property of Gohan (Goku's Earthling grand father). Gohan tried to nurture Goku, but Goku was too much too handle. But luck has come for Gohan and Earth. Gohan was walking in the forest one day, but suddenly Goku fell down a pit and bang his head against a rock. Sudden emerged a hero, a hero that will defend Earth against the universe most fearsome villain. And Goku's name will be written in the histories of DRAGON BALL Z/GT...