The DBZ story consists of different seasons known as sagas.The following are the names of the sagas and a brief discription about them.

Raditz Saga:This saga contains when Goku's older brother Raditz arrives on earth to recruit Goku to join and be a part of his saiyan heritage.In this saga Goku sacrifices himself to kill Raditand his son Gohan is kidnapped by Piccolo to be trained before the other saiyans Napa and Vegeta arrive.

Vegeta Saga:The saiyans finally arrive doing battle with the brave Z fighters.As most of them are killed(Tienshinhan,Chow-su,Piccolo,Yamcha)Goku arrives from training from the great King Kai.The battle goes on until Napa is killed by his own team-mate Vegeta.After this event Goku and Vegeta go on a one on one battle and finally through the help of his friends,Goku defeats Vegeta.

Frieza Saga:Krillian and Gohan finally arrive on Namek finding Vegeta and the strongest being in the universe,Frieza,are also looking for the dragonballs.As the saga moves on Frieza calls upon the Ginyu Force to eliminate his enemies.Afterwards,Goku defeats the Ginyu force going on to kill Frieza in his evil reign.In this battle Goku becomes a super saiyan destroying Frieza,but before Frieza can be killed he destroys Namek leaving our heros to escape on Frieza's ship.

Trunks Saga:This saga contains the arrival of the one we know as Future Trunks.In the future the earth is terrorized by andriods therefore Bulma,Vegeta's wife and Trunks's mother,creates a time machine and sends her son back in time to give Goku acure to his heart disease,in result the future is saved and the time line is rerouted to a good future also.