Other source:
To save his only friend, Piccolo makes the ultimate sacrifice, and dives in front of Gohan to block Nappa's attack. With Piccolo dead, Kami and the Dragon Balls are also gone, meaning that no one can be wished back. When all hope seems lost for Earth, Goku finally arrives. After giving Gohan and Krillin a Senzu bean, Goku learns what happened to his friends. Angered, he takes out his frustration on the hulking Nappa.
