The Saiyan Arc is the seventh arc in the Dragon Ball manga and the first arc in the Dragon Ball Z TV adaptation.
Set a few years after the end of the original Dragon Ball story (That is to say, it's the Dragon Ball anime that ended. The Original/Z split never existed in the manga). Goku comes to visit his friends at Kame House and introduces his son, Gohan. The happiness of his reunion is short-lived however when an alien who calls himself Raditz arrives and reveals Goku's true origins. After Raditz kidnaps Gohan to use as a bargaining chip against him. Goku is forced to team up with his old adversary Piccolo to fight Raditz. They succeed but at a high cost and it turns out Raditz was just the precursor to a much bigger threat on the way.
Five years have passed since the battle with the revived Demon King Piccolo. In that time, the Earth enjoyed a period of peace. Peace would quickly be shattered when a meteor-like pod crash-lands on Earth. Inside it is a man with long hair, heavy body armor, and a device on his eye that can tell how strong someone is. This man makes short work of a farmer and then begins his search for a man named Kakarot.
Piccolo, on the other hand, has been training in the mountains, only to quickly encounter the alien. Piccolo shows off his power, but the alien doesn't even feel it. But before the alien can attack, he finds someone else.
Meanwhile, there's a party on Master (Muten) Roshi's island, and Bulma, Krillin, the turtle, and Roshi himself are there. Launch and Tien Shinhan (Tenshinhan) are nowhere to be found, and Bulma outright refuses to let Yamcha come along, the first signs that their relationship is starting to fail. And soon, the man of the hour shows up, Son Goku himself! And he's brought a kid along with him, which everyone (including the audience, unless you started with Z) is shocked to find out is his son! The boy even has a tail and the Four Star Dragon Ball on his hat. Naturally, the former makes everyone wonder if the kid, named Son Gohan after his grandfather, has anything odd happen to him at night. Like when he sees the full moon. They go to bed early, so it's no issue.
And Goku's family tree becomes a lot more complicated when the alien arrives on the island, calls Goku Kakarot, and reveals himself to be his older brother Raditz.
But Goku doesn't remember any of it. After all, he suffered head trauma as a child, which Roshi explains gave the formerly wild baby Goku amnesia. Raditz is all too quick to explain. Raditz and Goku are part of a race of ruthless killers called the Saiyans. They make a business out of selling planets. In particular, they're in the business of cleaning off the planet of life. Don't expect to have to deal with any more of them, though, since a meteor wiped out their home planet, leaving only four survivors.
Goku, however, doesn't live up to Raditz's expectations. He doesn't have the propensity for bloodlust, has cut off his tail, and is disinterested in continuing the family traditions. But then Raditz notices that kid there with a Saiyan tail. If Goku won't join them, perhaps he will...
Goku resists, but it doesn't go well. Raditz steals Gohan and offers an ultimatum: prove his loyalty by killing 100 humans or his son dies. He then leaves Goku to think about it. Naturally, Goku is ready to face Raditz and get Gohan back. It's a tough day for the other humans. After all, both have died against the original Demon King Piccolo and can't be brought back with the Dragon Balls. Nonetheless, they elect to help him for his sake. But before any action can be taken, Piccolo shows up and proposes that he and Goku should team up.
Raditz imprisons Gohan in his pod for making too much noise but finds out that there's a high power level coming from it. He thinks that the thing on his eye (a Scouter, for those who are keeping score) is broken. Except it doesn't seem to be, since Goku and Piccolo show up, and their power levels are just fine. With the two being that strong and the readings being accurate, could the kid's power level be just as high as it says it is? To prepare for the battle properly, Piccolo and Goku take off their weighted training gear, increasing their power levels. But still, Raditz is more than enough for them, with just one energy blast tearing off Piccolo's arm.
Goku has nothing up his sleeve, but Piccolo's been saving an attack that he can do with one hand. The problem is it has to be charged, but Goku managed to at least fight Raditz to a standstill. The use of both the Kamehameha and Piccolo's attack, the Makankosappo/Special Beam Cannon, increases their power levels, making Raditz realize the Scouter's useless. Despite this, the first Special Beam Cannon misses, but Goku gets the upper hand when he grabs Raditz's tail, remembering how it caused him pain earlier.
Raditz, faced with the pain, begs Goku to let him go, saying he's purified, and Goku agrees. He's rewarded with an elbow in the eye, and a set of broken ribs. But before the violence can continue further, Gohan bursts out of his pod, displaying incredible power, headbutting Raditz for massive damage! But that power goes away, and Raditz decides he's too dangerous to be left alive. But before Raditz can murder Gohan, Goku pulls a Full Nelson on him, ready to perform a Heroic Sacrifice just to stop him. This time, the Special Beam Cannon is successful, leaving the two Impaled with Extreme Prejudice by the beam. Goku will be fine, though; the Dragon Balls can bring him back to life. But Raditz hears this fact from Piccolo and reveals his Scouter is also a radio, leading to his comrades, Vegeta and Nappa. And to top it off, those two Saiyans that Raditz was talking about? They're stronger than he is! Nappa indeed wants to bring Raditz back to life, but Vegeta decides to wish for him and Nappa to be immortal instead. Along the way, they remark on the fact that Half Saiyan Hybrids possess incredible power. Oh, and Piccolo can just regenerate his arm because he's a Namekian.
So let's recap, shall we? Our Chaste Hero has a son. Our strange-tailed human is an alien. And now he's dead. And we've only just begun. Are you on the edge of your seat? (If you were raised on Z first, your answer is probably "no.")
In the afterlife, Goku is met with King Enma, who determines he should go to heaven, and with a little help from Kami, sends him to train under King Kai to defeat the other two Saiyans, who will be on earth in one year. To do this, he must travel the million-mile road of Snake Way. It's a bit of a hard task, even without taking into account Goku getting lost twice, once on a trip to hell, the other in a palace that gives him enough food to fatten him up to be eaten by a giant snake.
Bulma takes the scouter to try and reverse-engineer it. As she's testing it out on Krillin, Roshi and the turtle, Yajirobe shows up to tell Krillin to bring Tien (who's out in the wilderness having to deal with Launch), Chiaotzu (who's with Tien) and Yamcha (who's now a professional baseball player) for some training. Piccolo, meanwhile, takes Gohan to train him how to use his power. His... training, if you can even call it that, mostly consists of forcing Gohan to survive in the wilderness. It goes about as well as you'd expect; Gohan gets stuck on a mountain after nearly being eaten by a dinosaur, and Piccolo has to bail him out twice. Once when he gives Gohan some rotten apples, the other when Gohan sees his first full moon... and goes Oozaru ("Great Ape" in the English translation). Piccolo quickly puts two and two together from Raditz mentioning the power of the tail, and takes out the moon... again. And since this isn't a universe with Magic Pants, Piccolo gives Gohan some new clothes, and a sword for good measure.
What follows is a long period of training, both for Gohan and for the others. Gohan goes on adventures in the wilderness before starting his training for real, and the Z Warriors go into the Pendulum Room to take on some illusion Saiyans, losing horribly. Goku eventually makes it to the end of Snake Way, where he encounters King Kai's (Kaio's) planet. After mistaking his monkey Bubbles for him, Goku meets the actual King Kai. The problem is, the gravity on the planet is extremely high, ten times that of Earth. It's perfect for training, though. Kai has an odd training regimen, consisting of telling jokes, catching Bubbles, and smashing a lightning-fast cricket named Gregory with a hammer before learning two powerful techniques: the Kaioken and Genki Dama/Spirit Bomb.
But even when Goku's revived, he can't come back in time for the arrival of the Saiyans, Vegeta and Nappa. They demonstrate their power by "saying hello," that is, wiping out an entire city with just two fingers. Vegeta scolds Nappa for it, though, because what'd happen if one of the Dragon Balls was in that city?
At a secluded area, Gohan, Piccolo, Krillin, Tien, Chiaotzu, and Yamcha face off against the Saiyans. Nappa reads their power levels, but Vegeta reminds him they mean nothing since they can be hidden. Besides, there's a much better way to test their power compared to Raditz: Planting the Saibamen. They're cultivated lifeforms who all have Raditz's power level. Tien is the first to go and succeeds before Vegeta blows up the Saibaman he was fighting. Krillin offers to go next, but Yamcha decides to take one for the team since Krillin can't be brought back. And take one for the team he does, getting blown up by a Saibaman in a Double KO. Krillin decides to not take any chances, and blows up the rest of the Saibamen, except for one that Piccolo kills.
Nappa decides it's time to begin his assault, picking Tien as his first victim. And Tien takes a lot of hits, to the point of losing an arm. Chiaotzu, in an attempt to stop him, blows himself up, and since he's already been brought back once, he's dead for good. Krillin and Piccolo try their hands at taking him on, but that doesn't work, either. Angered at Chiaotzu's death, and seeking to avenge him and keep him company in the afterlife, Tien uses the last of his energy to fire a one-handed Tri-Beam at Nappa. But even THAT doesn't faze him, and Tien dies. Even a three-hour delay isn't enough for Goku to show up, and when Gohan becomes Nappa's next target, Piccolo decides to sacrifice himself for Gohan, and takes the blast head-on, killing him, and by extension, killing Kami too, since they share the same life, meaning the Dragon Balls vanish. It's the Darkest Hour for the Earth: Our beloved cast from Dragon Ball is either dead or dying, they can't be brought back to life, and nothing our heroes are doing is doing any kind of lasting damage to Nappa.
And that's when Goku shows up at last. And he is not happy about the whole thing.
After finding out that Goku's power level is somewhere between over 8000 and over 9000, Goku dominates the fight with Nappa, to the point where Vegeta outright orders Nappa to give up. But when he tries to finish off his work on Gohan and Krillin, Goku uses the first of the techniques he learned from King Kai, the Kaioken, which multiplies all his capabilities, enough to break Nappa's back and paralyze him. Vegeta decides he's had enough of Nappa's failures, and kills him outright, calling him dead weight.
Taking the fight to a mountain range, Vegeta taunts Goku by saying that he's utter trash. Goku throws it back at him, saying that even the lowest can surpass the elite with enough hard work. The climactic fight involves a lot of power being thrown about, with Vegeta every step of the way. This forces Goku to push his Kaioken to times three, putting a strain on his body. Vegeta gets hit so hard, that he outright decides to blow up the planet with his Galick Gun. But Goku has a Kaioken-boosted Kamehameha waiting for him, leading to an epic Beam-O-War, Goku being the victor, but severely drained.
Vegeta only has one more course of action: to go Oozaru and finish off Goku. But the moon isn't around! That's okay, Vegeta has a method that he can use to simulate one, which leads to the tables being turned very quickly. Upon seeing the transformed Vegeta, Goku remembers how his grandfather was fatally stepped on by a large nocturnal gorilla, and assumes that Vegeta was this monster. A confused Vegeta then explains that all Saiyans can transform into gigantic apes upon seeing the full moon, so long as they have a tail. Remembering how his grandfather warned him to never look at the full moon, and how Kami made Goku permanently remove his tail in exchange for restoring the moon, our hero realizes that he was the giant monster that killed Grandpa Gohan and destroyed the Tenkaichi Budokai stadium! Tearing up, Goku promises to apologize to Grandpa Gohan when he meets him again in heaven, knowing that this is a fight he can't win. Goku eventually tries the Spirit Bomb, by gathering energy from all around the planet, but that doesn't work, mostly because he needs to stand still to use it, which Vegeta refuses to let him do. Even Krillin and Gohan's interference isn't helping at all... but then Yajirobe cuts off Vegeta's tail, reverting him to normal. He's still a colossal threat, but a little teamwork and a Spirit Bomb with Krillin substituting the firing does the job.
...or so we think. Vegeta survived that, too! Thankfully, Gohan's tail regrew, and that power ball's still there, so Gohan can transform and crush Vegeta (he gets his tail cut off again shortly afterward; Oozarus don't tend to stay transformed long in this series). And he's still alive! But he's decided to cut his losses while he's at it and summons his space pod to leave Earth.
Krillin won't have it, though, and is about to use Yajirobe's katana to kill him. Goku, however, has other plans. He wants to fight him again! Such a good opportunity can't be wasted, right?
Now what happens? The cast we've followed for years is either dead, useless, or hospitalized. And the monster who caused it all is still alive. Is there any way to bring our fallen comrades back from the dead?
Find out on the next exciting arc of ''Dragon Ball Z''!