At the start of Dragonball Z,Goku's brother Raditz came to earth looking for him.Raditz said Goku was not human(who would of guessed?Goku only had a tail.),but a Saiyin.Piccolo and Goku joined forces in order to beat Raditz.Goku grabbed Raditz from behind and Piccolo used his Special Beam Cannon it plowed through Goku and Raditz.Goku died,went to King Kai's,got training from him.On earth,Piccolo had trained Gohan,and Vegeta and Nappa had just arrived.Goku was wished back to life by Master Roshi and Bulma,Vegeta and Nappa killed off Piccolo,Chaozu,Yamcha,and Tein before Goku arrived,Gohan was about to be killed but Goku KO-Kened Nappa then Vegeta killed Nappa.Goku fought Vegeta,and Vegeta beat him up then,Krillan and Gohan came and helped Goku.Vegeta was in his Oozaru form until Yajrobe cut his tail off.Vegeta Was then hit with the Genki Dama.Then Gohan went Oozaru and fell on Vegeta.Vegeta left the planet.Gohan,Bulma,and Krillan went to the planet Namek looking for the Dragonballs.Goku healed and headed to Namek.When he got there,Gohan,Krillan,and Vegeta had a battle with the Ginyu force.Goku quickly beats everyone,except Captain Ginyu,who switched bodies with Goku.Well Captain Ginyu switched with a frog by accident,and Goku got his battered body back.Vegeta put Goku in a healing chamiber,Gohan and Krillan wished for Piccolo to come back and for him to be on Namek,Vegeta arrived and Guru died making the dragonballs stone.Freiza came for his revenge against Gohan,Vegeta and Krillan for destroying his chance at immortality.Freiza killed Vegeta,just as Goku arrived.Goku Began fighting Freiza,Goku Power Level at that time was 300,000 without the KO Ken attack.So,Goku was outmatched,so Goku knew he had to use the Genki Dama on Freiza.Goku did not want to kill Freiza.Piccolo tried to hold off Freiza ,so Goku could get the Genki Dama ready,he did.Goku through it at Freiza and it hit.Everyone thought the Genki Dama killed Freiza, it didn't. Freiza was ticked and in his rage he shot Piccolo and nearly killed him.Then, FReiza sealed his fate when he killed Goku's best friend Kuririn.This pushed Goku over the line,he snapped and went Super Saiyin.Goku told Gohan to take Piccolo,find Bulma,and get off the planet.The tides finally turned on the battle,FReiza slowly started to lose.Freiza thought he might lose so he fired his planet destruction beam at Namek,Freiza said the planet had five minutes left,Freiza said that he could beat Goku if he was able to reach his max.Goku let Freiza hit his max.At this time Freiza began to beat the crap out of Goku.Freiza knocked Goku into a volcano and this killed Goku.Gohan told Bulma that his dad was dead and that he would go fight Freiza.Gohan began to get beat by Freiza.Freiza told Gohan that his dad begged for his life,Gohan began to fight harder,but he still got beat.ON earth,Kami had Mr.Popo found the Dragonballs,King Kai said he had a wish,it was to wish everyone killed by Freiza to be revived,and since Guru died of heartache because his people were killed he would be revived also,and the Namekian Dragonballs would function again and they still had one wish left.The Nameks were revived and so were the Dragonballs,Dende was told to make the wish that everyone except for Freiza was wished to earth.Back to Gohan vs Freiza,Gohan's attacks didn't hurt Freiza,then a golden flame came out of the ground and Goku was revived.Gohan left,Freiza saw the Namekian Dragon and raced off to get to the Dragon,Goku just was a little too slow,Freiza made it to the Dragon before Dende or Goku did.Freiza wished for immortality,but the wishs have to be said in Namek.Then Vegeta(about time) showed up from his grave to help Goku beat Freiza.But Dende made the wish.Goku said he didn't want to go so he stayed,what an idiot,he and Freiza fought untill the planet had a few seconds before it exploded.Freiza cut himself into three pieces ,then Goku blew him away.
Enter the Andriod Saga,after Goku returned to earth,King Cold and his son Freiza,who was re built by his dad,came to kill Goku.Also arriving a boy named Trunks,who just appeared,told Goku about the furture,Goku asked how he died Trunks told him that he died from heart disease,Goku was dissapionted.TRunks gave Goku some heart medicine.Then he killed King Cold and then he told Goku about the Andriods.Goku became sick.So Vegeta and Trunks and the Z-fighters went to kill the Andriods.They did.For the most part, Vegeta killed 19 and Dr. Gero(#20) ran to activate !7 and 18.Enter Cell.Cell,the strongest character overall,came to absorb 17 and 18. If he could absorb the two Andriods,his would be close to immortal,he absorded them,and since Cell knew he was so strong he made the Cell game.Which was a basic fighting tournament,Goku and Cell fought,Cell told Goku to eat all the senzu beans wanted to during the battle,Goku did,but it didn't help much.The Z-fighters began to attack Cell at once,Cell decided to use his special attack,which causes all things within a planet to self-destruct including Cell.Cell told them what he was going to do,Goku grabbed him and teleported to a different sola system Cell exploded and killed Goku.But like all DBz enemies,it doesn't end there.One of Cell's brain cells lived though the explosion,and from that Cell recreated his body and went back to earth.Gohan and Cell fired two beams at each other and Vegeta shot Cell from behind,this distacted Cell from Gohan,Gohan shoved the beam at Cell the this killed Cell.
The Buu Saga,Vegeta fused with Buu to make Majin Vegeta.Goku fought Majin Vegeta,M.Vegeta saw the error he had made trying to take over the world,so he killed himself,yet he didn't kill Buu.Goku stated fighting Buu,Goku reached SSJ3,but he still couldn't beat Buu so he asked Vegeta a favor:that they would fuse.Vegeta fused with Goku to form Vegetto.Vegetto went SSJ and did the Big Bang Attack on Buu.