Son Goku, now a grown man raising his son Gohan in peace, learns he is a Saiyan warrior when his brother Raditz arrives on Earth and kidnaps Gohan to force Goku into service. Goku teams up with his old rival Piccolo to rescue his son, but the fight draws the attention of two more Saiyans, prince Vegeta and Nappa, who are already headed for Earth and its Dragon Balls.