The Saiya-jin saga is what starts off DBZ. Radditz, Goku's older brother, comes to earth. He is checking up on his little brother, and to have Goku join him with the other remaining saiya-jin. Goku refuses, so Radditz kidnaps Gohan. Goku goes to save his son, accompanied by his enemy, Piccolo. As Goku held Radditz from to blast both brothers through the stomach, the only way to kill Radditz. As both brothers lay on the ground dying, Radditz comments on the heroic decision made by his brother (sacrificing his life in order to kill Radditz). Piccolo calls Radditz an ass, for Goku will be back soon. Piccolo, since Radditz was dying, told Radditz about the dragon balls. Radditz tells Piccolo that he has transmitted the information with his scouter to his partners in space -- two saiya-jins with strength far surpassing his own. The saiya-jins will come for these dragon balls and make them pay for killing Radditz (or so he thinks o_O). Goku asks Radditz how long it will be before they arrive, and the answer is one year. With that, Goku and Radditz finally kick the bucket, but Goku's body disappears.