The first series of Dragonball Z, Gokou has a reunion with his old friends and introduces him to his five year old son, Gohan. But as they celebrate a saiyin alien seeks the one called Gokou...
The saiyin alien is called Raditz as he introduces himself to Gokou, and that he is actually his brother. We learn that Gokou is actually a saiyin and arrived here at Earth in a spaceship. Gokou's real name is Kakarot and Raditz then asks Gokou to join him in his quest for universal domination. Gokou refuses but Raditz will take no for an answer. He takes Gohan and threatens to kill him unless Kakarot kills innocent people. Gokou decide to rescue Gohan by killing Raditz, so suprisingly Piccolo and Gokou team up to vs the saiyin alien. Before the fight, Raditz stores Gohan in his spaceship where he cant escape. So the first fight begins, Gokou and Piccolo both start fighting Raditz but dont even touch him. So they both decide to take off their weighted clothes but there is still no improvement. Piccolo gathers energy to do his special beam cannnon while Gokou stalls some time. He fires the beam but amazingly Raditz dodged it. As the fight goes on, Gokou grabs Raditz tail which is a saiyins weak point. Raditz begs to let his tail go and promises to leave Earth as once, so the kind-hearted Gokou has to lets go. Raditz double-crosses Gokou and starts beating him up. Gohan hears his fathers crys, he goes berserk and headbutts Raditz right in the stomach. Raditz is stunned how a young child could hit him, while this happens Gokou grabs Raditz tail and he is weakened once again. Piccolo summons another special beam cannon and fires it at Raditz, since Gokou was holding Raditz he died also. As he dies Krillin mocks him that Gokou will be brought to life again by the Dragonballs. Raditz explains that the device he uses to detect energy levels are also used to communicate. He sends his last message about the Dragonballs to his two comrades and dies.
One year later...
We find out that the two conrades are Nappa and Vegeta, they intend to find the Dragonballs on Earth to wish for immortality instead of bringing back Raditz. Gokou has been training at King Kai's planet for one year now and Bulma is still gathering the Dragonballs to revive him. But the saiyins arrive and the Z warriors are left to battle them without Gokou. First they plant seeds in the ground to grow Saibi-men, Yamcha goes to fight first. He starts beating the crap out of the Saibi-man but he grabs Yamcha and commits suicide by blowing himself up killing both of them. Everyone is shocked, especially Krillin as he aims a huge energy blast at the Saibi-men and the saiyins. He kills all of the Saibi-men and thinking that he also killed Nappa and Vegeta. But they both emerged out of the dust and everyone is shocked once again. So Nappa begins to fight, in a series of battles, Chauzu sacrifices himself to kill Nappa but fails, Tenshin-han dies by using up his strength to try to kill Nappa, and Piccolo dies when he covers Gohan from Nappa's fireball. Hope seems to be gloom for Gohan but finally Gokou arrives! Gokou starts to fight Nappa and easily defeats him. Nappa is shocked that a low-class saiyin like Gokou could beat him. Vegeta sees Nappa's uselessness and kills him with a single fireball.
Gokou and Vegeta decide to fight alone and so they fly off leaving Gohan and Krillin to head home. The fight begins to take place and Gokou realises that Vegeta is too strong, so Gokou uses his Kaioken attack. Yet Vegeta is still slighty powerful then Gokou, Gokou must go one more level up, Kaioken x3 attack. The stress on his body is enormous and he starts to beat Vegeta around. Vegeta is enraged and sours up into the sky to fire a beam, called Gallick-Ho. Gokou starts to power up his beam as well and the two beams collide. There is a standstill so Gokou pumps up to Kaioken x4. Doing so his beam becomes more powerful than Vegetas and sends his into the atmosphere. Gokou's body is seriously damaged though, and he knows he may not be able to take much more damage.
Meanwhile, Vegeta escapes the beam and realises that the only way to beat Kakarot is to transform. He flys back down to Earth and hurls a ball of energy into the air, which perfectly simulates moonlight. Vegeta starts to transform and beats Gokou around. Gokou uses his Solar flare which buys him enough time to perform a Genki-Dama. But the ape recovers and fires a enery blast before he can use it. Vegeta grabs Gokou and starts crushing him with his hand, as this happens Gohan and Krillin arrive. Krillin fires a destructo disc to try to cut off Vegetas tail while Gohan distracts him but fails. Out of nowhere Yajirobe cuts off him tail with his sword and Vegeta turns back to normal size. Vegeta and Gohan start to fight to buy some time for Krillin. Gokou gives Krillin the remaining energy he has and hurls it at Vegeta, amazingly he dodges it but Gohan re-directs it back to Vegeta. Doing so Vegeta is once again sent to the sky.
The Z warriors celebrate in their victory but as this happens, Vegeta falls back from the sky. He wakes up and once again starts to kick everyone around. But Gohans tail grew back and he turns into Oozaru, Vegeta manages to cut off Gohans tail but is squashed by him when he transformed back. Vegeta is badly injured and now calls for his spacepod. He shoots off and returns from where he came from leaving Earth in peace once again.
