Radditz then took Gohan and said to Goku that if he didnt kill 100 people he wouldnt get his son back, after that he flew off to his space pod. Goku was about to take of to fight Radditz when Piccolo appeared (Piccolo was not an allie at this part in the series). Bulma gave them the dragon radar as it would be easier to find Gohan as he had a dragonball on his head.
After finding Radditz , Radditz checked out Gokus and Piccolos Powers and saw that they were puny compared to him, Piccolo and Goku revealed that there were wearing weighted clothing so after taking them off there powers increased. The fight begun and Piccolo and Goku were losing, Piccolo announced that he had a new technique but it needed to be charged up so Goku fought alone. Piccolo missed with his first Beam Cannon and then Radditz detected a PL of 710 which was much greater than Goku and Piccolo. It was Gohan and he did a flying headbutt into Radditz , Radditz was about to kill Gohan until Goku managed to grab him from behind and sacrifice himself while Piccolo shot his special beamcanon at both of them.
Piccolo told Radditz how Gokus life would be restored then Radditz said that two much stronger Saiyans would come to earth and destroy it.
After hearing this Piccolo took Gohan and told Krillin and Bulma that he would train him in so that they would be strong enough for the Saiyans.

Krillin, Yamcha, Tien, Choat-zu and Yajirobe were all taken to Kamis place to train also despite none of them being storng enough. Goku had to travel along Snake way til he got to King Kaios where he would train to get much stronger. At King Kaios he learned the art of Kaio Ken and he learnt the Genki Dama.