This is the series where it all began. In this page, I will give you a brief summary of what happened in this series. More detailed summaries may be found elsewhere in the web. Anyway, the story starts out when:
Gokou has a reunion with his friends and introduces them to Gohan, his five year old son. However, a Saiyan alien lands on Earth and to seek Gokou. He introduces himself as Raditz, Gokou's older brother, and asks Gokou to join him in the Saiyan quest of universal destruction. But, when Gokou refuses, Raditz kidnaps Gohan to blackmails Gokou to kill innocent civilians. However, Gokou remains loyal to Earth and decides to rescue Gohan through another method-- by killing Raditz! Surprisingly, Piccolo allies with Gokou and the first fight of Dragonball Z began. Piccolo decides to gather energy to do a super fireball on Raditz. Meanwhile, Gokou stalls time. At the end, Gokou puts his brother in a hold. At the advantage, Piccolo unleashes his fireball, which blasts and hits both Gokou and Raditz! Klilyn finds the fighters and laughs at the dying Raditz as he mocks him that Gokou will be brought back to life through the power of the Dragonballs. Gokou's brother replies that the device he uses to detect energy levels can also be used for communication. He sends the news about the Dragonballs to his two comrades, and dies.
Because Piccolo discovered that Gohan had hidden powers when Gohan unknowingly headbutts and damages Raditz, he kidnaps Gohan in an attempt to train him. Gokou, rather than retiring in Heaven, is sent on a quest to run on Snake Way and to seek King Kaiou to receive training for the upcoming fight with the upcoming Saiyans. The rest of the Z warriors (Klilyn, Yamcha, Tenshin-han, and Chauzu) are gathered to receive special training from Kami.
Season #1 of Dragonball Z on American television ends here.
One year later, Nappa and Vegeta (the evil Saiyans) arrive to Earth. (But, they intend to find the Dragonballs to be granted the wish of immortality rather that to bring back the life of their unworthy comrade.) First come the battle against the Saiba-men (little Green monsters) that Nappa planted. The Saiba-men fight, but are eventually killed by Vegeta and Klilyn. (At one of these fights, Yamcha is killed.) After their defeat, our heroes fight Nappa; Vegeta stands in the background and watches. In a series of battles, Chauzu dies as he sacrifices himself in an attempt to blow up Nappa; Tenshin-han dies by using up his strength to try to kill Nappa; Piccolo dies when he covers Gohan from Nappa's fireball. Finally, Gokou arrives and easily defeats Nappa. Vegeta sees Nappa's uselessness and kills him with a single fireball.
As you all can guess, the remaining Z warriors begin to fight Vegeta. Gokou begins to fight Vegeta. The odds are against Vegeta, so Vegeta creates a energy ball that substitutes the moon. Then, he turns into his full moon stage and turns into a giant gorilla. Our heroes get kicked around, but Vegeta later gets his tail cut off by Yajirobe. Gokou donates energy from his Tenki-Dama to Klilyn. This fireball hits Vegeta, but Vegeta survives. Meanwhile, Gohan's tail grows back. Gohan turns into his full moon stage and kicks Vegeta around. Later, Gohan gets his tail cut off by Vegeta and finally turns back into a little boy... landing right on top of Vegeta. Vegeta, weary and defeated, crawls to his space shuttle and leaves Earth.
This is not the end of Vegeta...