The episode opens on a peaceful farm when a space pod crashes down onto Earth into a farmer's marijuana patch. Piccolo is interrupted by the alien, who confused him for someone named "Kakarot." At Kame House, the alien arrives and explains to Goku that he is actually part of an alien race called the Saiyans and that they are brothers. Raditz, the Saiyan, requests Goku to join him and destroy everyone on the planet. Goku declines, so Raditz takes Gohan and flies away.
Piccolo and Goku catch up to Raditz and challenge him to a fight. After he notices they are getting stronger from removing clothing, he begins to get naked until Goku informs him that they are just wearing weighted clothing. Radditz, embarrassed and angered, attacks Piccolo and Goku. Goku dies. Piccolo then grows his arm back and flies off with Gohan.
Nappa and Vegeta overhear Master Roshi talking about the dragon balls over Raddit'z scouter. Piccolo tells Gohan that he will train him. In the afterlife, Kami tries to convince Yemma to let Goku travel on Snakeway to King Kai's planet to receive training to battle the Saiyans coming to Earth.
Goku runs over Snake Way and falls off into Hell meeting two ogres named Goz & Mez. Goku tricks them into telling him how to escape and get back on Snake Way. On Earth, Kami assigns Mr. Popo to train Earth's warriors. Mr. Popo knocks Krillin off of the look-out when Krillin dares to ask a question.
Goku finally reaches the end of Snake Way and jumps over to King Kai's planet. King Kai agrees to train Goku. Vegeta and Nappa stop at planet Arlia to keep Nappa busy. They introduce themselves to the Arlian King, killing all of the elite guards. Vegeta destroys the planet, and they continue their trip to Earth. On Earth, Piccolo begins his training with Gohan. Meanwhile, the superfriends conceder their options in dealing with the Sayians. Superman quickly shoots down Aquaman's plan to use Whales.
Mr. Popo takes the Z-Fighters and teleports them to another dimension. Meanwhile, King Kai promises Goku that he will commence their training. The magical dragon, Shenron, is summoned and brings Goku back to life.
Nappa and Vegeta land on Earth and fly off toward the strongest power level. Piccolo senses the approach of the Saiyans as Krillin arrives. Nappa explains to Piccolo that Piccolo is a Namekian. Vegeta decides to plant the Saibamen explaining that each is as powerful as Raditz.
At Kame House Master Roshi and Bulma watch on TV as Yamcha is killed by a Saibaman. Nappa steps onto the battle field and attack Tien, removing his hand. Tien escapes, making Nappa think he wants to play tag. Chiaotzu hops onto Nappa's back and uses self-destruct. Chiaotzu's death was in vain, as Nappa has barely a scratch on him. Tien uses a final attack on Nappa, using up all of his energy and causing his death.
Gohan attempts to wake up Piccolo, who was knocked unconscious by Nappa. Krillin assures Gohan that his father, Goku will arrive, citing that he's never let them down, but then it cuts to Goku back at Princess Snake's palace eating another huge meal. Snake reminds him that there was something he had to do about Saiyans. Realizing his negligence, Goku rushes right back on Snake Way and continues his way back to Earth.
Goku requests that he and Vegeta take their fight elsewhere, since fighting on a battleground littered with the corpses of his fallen friends just doesn't feel right. Relocating to a desert, Goku gives Vegeta one opportunity to leave Earth and never return, so no more blood needs to be shed before their fight begins. Vegeta disregards Goku's offer as tripe and belittles him for growing soft from living on the planet for so long.
Vegeta rages at having been surpassed by Goku. Vegeta creates an artificial moon and transforms into a giant ape. King Kai tells Goku to use the spirit bomb to defeat Vegeta. Goku begins gathering the energy he needs but forgets to remain well hidden from the Saiyan ape, getting pummeled into the ground instantly...
Vegeta's completely overjoyed with his childish, idiotic partner finally dead. However, he still intends to kill everyone on Earth, including Goku and his friends. Goku decides to face Vegeta on his own and instructs Gohan and Krillin to get as far away from the battlefield as possible.
