This is the sequel to the original series, Dragonball.  The star of the show was Goku, who was from a distant planet.  He had a tail and possessed great strength.  He and his friend Bulma went around collecting seven orange spheres called Dragon balls.  When gathered, a mystic dragon would appear and grant any wish that you wanted.  Dragonball Z takes place after Goku has grown up and now has to protect the Earth from evil.  The series concludes with Dragonball GT (grand trip) which takes place after Goku has been dead for many years.