Unlike it’s predecessors dragon ball and dragon ball Z, dragon ball GT is not based on the original manga or made by the same person. In dragon ball GT Goku is transformed into a child from a rather
inadvertent wish made by emperor Pilaf (from the first dragon ball series) using the black star dragon balls. The black star dragon balls then depart and spread themselves all over the galaxy (as opposed to
the regular dragon balls which remain on earth), If the dragon balls are not returned in one year, the Earth will be destroy so Goku, Trunks and Pan set off on a journey to recover them.