episode 1:

Five years have passed since the 23rd Tenkaichi Budokai. A one-man space pod falls to earth, and a long-haired alien appears from inside, looking for someone named "Kakarrot." 

Elsewhere, Goku and Chichi have a spoiled son, Gohan, and have been living on Mt. Paoz. Just before a trip to the Turtle Hermit's island to introduce him to Goku's friends, Gohan cavorts with a hat-stealing saber-tooth tiger, falls into a river and unknowingly demonstrates a remarkable hidden talent before Goku saves him

this alien encounters Piccolo, homing in on his strong power signature. Although he had been honing his skills in order to defeat Goku, Piccolo is overcome with fear before the terrible power of the alien who suddenly locates another strong power signature and heads off in that direction