This episode starts with a ship flying across space, until finally landing on Earth. A farmer working in the field sees the ship land, and goes to check it out. It is like nothing he has ever seen before. A strange man emerges from the ship. He looks just like an Earthling, but has funny armor on, the farmer shoots the alien, but the alien catches the bullet! And then he flings it right back at the farmer, killing him instantly!

Meanwhile, our friend Goku getting Chi-Chi some firewood before going to get Gohan. Goku has an important thing to do today, to go and see Master Roshi and all of his other old friends at the place where he trained!

Meanwhile, we see an old enemy meditating, it's Piccolo! But he senses something coming, and the strange alien arrives right in front of him! He says that he is sorry and thought that he was "Kakarrot", someone he is searching for. The alien tries to blow him up, but when he senses "Kakarrot", he flies off, leaving Piccolo stunned at the horrible power.

Meanwhile, Goku is looking for Gohan, and finds him stuck in a tree, and picks him up, and then fly on Nimbus to Master Roshi's. The next scene is Master Roshi's, where Krillin and Master Roshi greet Bulma, who has just arrived. They ask her where Yamcha is, only to yell out that he is out, and that she is upset with him that he is out playing baseball. Goku finally arrives, and they all wonder who Gohan is, and when Goku tells them that he is his son, they are all shocked. Bulma asks Gohan how old he is, telling her that he is 5 and a half. He says that he wants to be an orthopedist when he grows up, making Bulma and the others confused at the fact that he isn't fighting. Goku says that Chi-Chi doesn't let Gohan train and that she makes Gohan study more than anything else. They all notice that Gohan has a tail, but Goku still doesn't know about the tail thing, so when they ask him if Gohan watches the full moon, Goku says no, and that he sleeps early.

Goku then senses something, something coming straight toward the island, and it's the alien! The alien calls Goku "Kakarrot", making Goku a little bit confused. Krillin tries to talk to the alien, but he slaps Krillin with his tail and he flies into a rock. He is alright, just a little beat up. The alien introduces himself as Raditz, Goku's big brother! Goku can't believe it. Raditz tells Goku that he is from the Saiyan race, a fighting race from a distant planet that was blown up by a comet! Raditz asks Goku about his tail, saying that it was removed, making Raditz very upset at him, saying that his tail gives him more power, and he got rid of it! Raditz asks Goku if he was hit on the head, making Master Roshi reveal that Goku was once hit on the head when he was a little boy, and that his grandpa Gohan found him a little round pod, and Gohan tried to take care of him, but he was too wild, until one day he fell into a pit, and hit his head, changing him from a monster to a happy loving boy. Raditz tells Goku about the Saiyans, and how they are sent to planets to rid the planet of inhabitants. He asks Goku to join him, but Goku refuses, making Raditz see Gohan's tail, and says that he will take him instead! Goku tries to fight Raditz, but is beaten up, and sits in the water, defenseless, as Raditz is about to leave with Gohan!