Seagulls fly overhead as a ship sails past a large whirlpool. Two sailors watch the whirlpool in awe when they are interrupted by a sound. They look down and see a barrel floating beside the ship.
Inside the ship, a dance is going on. A girl stands at a window looking out at the water. A young man approaches and asks if he can have a dance. She nods and joins him.
Outside, the sailors try to grab the barrel with a hook. They are not having any success and the lookout says they suck. Suddenly he spots something. The two sailors finally manage to grab the barrel and they haul it onto the ship. The lookout meanwhile is sweating and trembling in fear. As he watches, a pirate ship emerges from behind a nearby island.
He shouts down to the two sailors and they run off shouting of an enemy attack. The pirate ship fires and explosions rock the ship. The sailors burst in on the dance and shout to the captain about the pirates. The captain tries to calm everyone but they all run around in a panic.
On the pirate ship, the captain, a large woman holding a large spiked club, calls out to a boy named Coby and asks him who the most beautiful woman on the ocean is. Coby quickly replies that it is her and she agrees, telling the crew to pull alongside the other ship.
With all the rocking of the ship, no one notices that the salvaged barrel has rolled off down some stairs. It hits a door and bounces into a room and rolls into a hole. Meanwhile, the girl Nami, runs out onto the deck and, upon seeing the pirate ship pulling alongside, promptly runs back inside.
The pirates throw grappling hooks and Alvida orders them to board the ship and show the power of Alvida. The pirates board and begin their attack but Coby is frightened and an irritated Alvida kicks him over.
In the dance hall, the pirates have surrounded the guests and the crew and he says they are only there for their valuables. Alvida comes forward and says that any people who resist will be thrown in the ocean. Nami watches all this then smiles and throws off her dress to reveal a pirate's outfit.
Meanwhile, Coby finds himself in the kitchen. He looks around and sees an unusually large barrel and he walks over to examine it. At the same time, Nami swings over to the pirate ship and quickly takes out a pirate that she runs into.
Coby is rolling the barrel towards the door when three pirates walk in and ask him if he is hiding from the battle again. He replies that he is just trying to bring back the huge wine barrel. The greedy pirates say that they will lighten his load and they set the barrel right side up. One pirate steps forward to open it.
Suddenly out of nowhere, a pair of fists comes flying out of the barrel, smashing the pirate in the jaw and sending him flying while the others look on in shock and confusion. A boy wearing a straw hat rises out of the barrel, following the fists and he shouts that he had a great nap.
The boy looks around and sees the unconscious pirate as well as the other two pirates staring at him like he is a monster. He asks what is going on and who they are and they draw their swords on him. The boy is oblivious to them and he asks Coby if he has any food.
Infuriated, the two pirates swing their swords and the boy turns to look at them while Coby covers his eyes. The broken blades spin and stick in the ceiling and the boy asks them what they are doing. The pirates stare at their broken swords and the boy in dismay.
They look at him and ask him who he is. He introduces himself as Monkey D. Luffy and says it is nice to meet them. The two pirates race out of the room dragging their unconscious companion. Luffy asks what is up with them and Coby wakes up from his trance telling him to run before they come back with reinforcements.
Luffy is not concerned at all and says that he is really hungry. Coby tries to get him to act but Luffy starts sniffing and he heads to a door where he finds loads of food. Coby closes the door and says that they might not be found there.
Coby turns to Luffy who is stuffing his face and says his name is Coby. Luffy continues eating like he did not hear and asks if they are on a pirate ship. Coby explains that the ship they are on is currently being attacked by Alvida. Luffy says it does not really matter and asks if there are boats since his was sucked into the whirlpool.
Coby comments that Luffy should be dead and Luffy laughs saying that it surprised him. He asks Coby if he is a pirate and Coby explains his story. He went to go fishing but instead of boarding his boat, he got on a boat going to a pirate ship.
Coby continues that he has been working for them for the last 2 years so that they don't kill him. Luffy says he is really dumb for getting on a pirate ship and says he should run away. Coby shakes his head saying that it is impossible. Coby says that he is terribly afraid of Alvida and if she found out he would be killed for sure.
Luffy laughs while saying that Coby is a coward. Meanwhile, up on the deck, Alvida tells her men to hurry up so they can leave before the Marines arrive. On the pirate ship however, Nami has gathered up all the treasures into a large sack.
The two pirates who encountered Luffy jump out onto the deck and tell Alvida that there is a problem. They start stuttering about a barrel and a monster. Alvida gets angry and asks who is a monster. She throws her club and the two pirates duck but they are holding the unconscious pirate in their hands and he gets smashed off the ship and out of sight.
The club lands on their heads and they explain that a weird person came out of a barrel down below. They say he might be a bounty hunter.
Down below, Coby asks Luffy what he was doing in a barrel. Luffy smiles and says he is going to be the Pirate King.
Coby goes into a daze and then he stands up saying that the Pirate King is someone who has everything in the world. Coby shouts at Luffy that he must be going after "One Piece" the greatest treasure of them all. Coby cannot believe what he is hearing and he says it is impossible but Luffy tells him to calm down.
Luffy says it does not matter if it is impossible since he is doing it because he wants to. Looking at his straw hat, he says that he decided to become the Pirate King. He adds that he does not care if he dies fighting for it. He then walks off saying he will look for a boat.
Coby thinks about what Luffy said and comments that maybe he could join the Marines like he had always dreamed. Luffy says he can do whatever he wants and Coby continues shouting that he would catch Alvida but they are interrupted when the ceiling caves in and debris rains down on them.
The smoke clears and Alvida asks Coby who he is going to catch. Coby trembles in fear and Alvida glares at him. Luffy looks on and a bunch of sword blades pierce the wall behind him. Alvida looks at Luffy then comments that he is not the pirate hunter, Zoro.
Alvida asks Coby who is the most beautiful but before he can answer Luffy asks who the fat lady is. Coby and Alvida freeze in shock and above, the pirates listening start sweating.
Alvida freaks and swings her club at Luffy but he dodges and leaps out through the hole in the roof bringing Coby with him. The two pirates above attack Luffy but he dodges their swings and beats them up. More pirates attack but he dodges again. A pirate tries to attack Luffy from behind but he grabs him and throws him into his companions saying that attacking from behind is not fair.
Luffy turns around to find the other pirates glaring at him and he runs away shouting that it is not fair to attack with more people. He passes the mast and grabs it with one hand but keeps running. Much to the pirates' surprise, his arm stretches and he smiles at them saying he is just kidding.
They freak and run in the opposite direction and Luffy flies at them like a rubber band shouting out "Gomu Gomu no Rocket!" Alvida crawls out of the hole in time to see Luffy shooting into the pirates and she stares in shock wondering what he is.
Coby asks him what he is and Luffy explains that he is a rubber man. Alvida asks if he ate one of the Devil's Fruits and Luffy replies that he ate the Gomu Gomu(rubber) Fruit.
Alvida says he has some moves and asks if he is a bounty hunter but he says he is a pirate. Alvida questions about his crew but he says he will get one eventually of about 10 people. While they are speaking, Nami sneaks out onto the deck and into a waiting boat.
Alvida says that if he is a pirate then they are enemies and though Coby warns him to run, Luffy faces her. Alvida asks Coby what he was going to say about her being number one and he says that Alvida is the number one stinking ugly old hag. The pirates all freeze in total shock and Alvida glares at him in fury.
Luffy laughs and Coby states that he will join the Marines and fight pirates like her. She calls him a little brat and attacks with her club but Luffy jumps in the way and takes the club to the head. He smiles and says it doesn't hurt since he is rubber.
He swings his arm back and it stretches then he shouts out "Gomu Gomu no Pistol!" His fist shoots back and hits Alvida in the stomach and she goes shooting off the boat. The unlucky pirate that Alvida knocked away floats in the sea admiring the sky when a shadow blocks his view and Alvida lands on him.
Luffy turns to the other pirates who are still in shock and tells them to give Coby a boat since he is going to join the Marines. Coby smiles and the pirates run to obey.
Suddenly, a barrage of cannon fire hits around the ships and Luffy sees the Marines on the horizon. He says Coby should join them but Coby says they would arrest him first. Nami is below packing up her treasure onto her small boat when Luffy and Coby fall from above in another boat. Luffy and Nami make eye-contact and then they head away.
Later on after they have escaped the Marines, Coby asks Luffy if he is heading to the Grand Line. Luffy says he is and he will need a strong crew. Luffy asks Coby about the Pirate Hunter, Zoro and Coby says that he was captured by the Marines.
Luffy comments that he must be weak but Coby says that Zoro is very terrifying, like a beast. Coby questions why Luffy is asking and Luffy says that he will get Zoro to join his crew.
Coby stares in wonder at Luffy's recklessness then starts shouting that it is impossible until Luffy is forced to hit him to calm him down.
On a distant island in a Marine base, the Pirate Hunter Zoro stands tied to a wooden stake.