The Story of One Piece:
Many years ago, the "Pirate King" Gold Roger was executed before the world. With his last words, he declared that anyone who wanted his treasure "One Piece" was welcome to it, but they would have to find it first. Since then, a new age of pirates has emerged with countless men taking to the seas, trying to find Gold Roger's hidden treasure and become the new Pirate King. This is the story of Monkey D. Luffy, a pirate who seeks One Piece and, as he so often boasts, will become the Pirate King.
One Piece - The legendary treasure left behind by Gold Roger. No one knows exactly what One Piece is, or the exact nature of it, but whoever claims it will become the Pirate King.
Devil Fruit - Mystical fruits scattered throughout the world that grant whoever consumes them great power at the cost of the never being able to swim again. Devil Fruits are divided into three types: Paramecia, Zoan, and Logia. Paramecias have a very broad range of powers, but they usually alter the users body in some way, allow the user to create something, or allow the user to manipulate the environment in some way. Zoans allow the user to transform into an animal. Logias, widely considered to be the most powerful, allow the user to become, create, and control an element, such as sand, fire, smoke, etc.
Seastone - A mysterious element that carries the essence of the sea. Various items, such as weapons, nets, and handcuffs, can be crafted from seastone. Devil Fruit-users are quite susceptible to it, just as they are to the real sea, and thus it is often used to combat or restrain them.
Grand Line - The equator equivalent of the One Piece World, it is a sea that circles the entire world. Whoever seeks One Piece must traverse the entire Grand Line; no easy task as the Grand Line is plagued with dangerous and unpredictable sea storms, climate changes, sea monsters, and all other forms of seafaring hazards. And, of course, one can't discount all the other pirates, bounty hunters, and marines that will try to stop those who seek One Piece.
Log Pose - A compass specially designed for navigating the Grand Line; all seafarers without one will be lost. The needle of the compass points to a certain island on the Grand Line, and the crew must go to that destination. After being on the island for a certain amount of time, the Log Pose "sets" and the crew may proceed to the next island.
Berries - Currency of the One Piece world
World Government - As the name implies, it's the ruling government of basically the entire world. As the story progresses, we slowly discover that the World Government is not as benevolent as once thought; filled with corruption and tyranny and hiding a dark secret.
Marines/Navy - The main military force of the World Government and, like the governmental body that supports it, is plagued with corrupt and tyrannical officers that will stop at nothing to stamp out all pirates in the name of "absolute justice." Though there are some good eggs as well.
Seven Warlords of the Sea - Seven extremely powerful pirates who have agreed to serve the World Government in exchange for amnesty from their past crimes. At this point in the story, five have been named and four have been seen. Luffy has already defeated one of the Warlords, Sir Crocodile.
Fishmen - Half-man/Half-fish hybrids that naturally have the ability to breath underwater. There is usually much ado about racism whenever they show up.
Poneglyphs - Large stone slabs scattered throughout the Grand Line that are inscribed with an ancient language that very few are able to read. They supposedly contain the "true history" of the world.
The Will of D. - A mysterious force in the One Piece world. All those who have "D." in their name seem to possess some kind of power.
Monkey D. Luffy - Captain of the Strawhat Pirates. As a boy, he ate the Gum-Gum Fruit, which gave him the ability to stretch like rubber (frankly, his mastery of it puts Mr. Fantastic to shame). Naive, impulsive, simple-minded, but with an indomitable will, he's determined to find the legendary treasure One Piece and become the Pirate King.
Roronoa Zoro - Luffy's first mate and swordsman of the Strawhat Pirates. Though serious, determined, and snarky, he can also be a bit dim at times, especially when it comes to finding his way around. He uses the three-sword style: one sword in each hand and one in his mouth. He dreams of becoming the world's greatest swordsman.
Nami - The navigator of the Strawhat Pirates. Despite her greedy and deceptive nature, she is perhaps the most level-headed member of the crew and manages (or at least tries to) keep all the crewmembers wild behavior in check. She fights with the Clima Tact, a device that can create miniature weather effects. She dreams of creating a map of the entire world.
Usopp - The lying cowardly sharpshooter of the Strawhats. Though he may not seem like a valuable ally at first, you can definitely count on him in a pinch and he's proven his mettle against pirates, fishmen, and bounty hunters alike. He dreams of becoming a brave warrior of the sea.
Sanji - Amorous to the ladies, and crass to everyone else, Sanji is the chain-smoking chef of the Strawhats, who literally kicks butt with his kick-based fighting style (a chef's hands are his most valuable asset after all). He dreams of finding the legendary sea All Blue, which is believed to contain every type of fish in the world; a chef's dream.
Tony Tony Chopper - The Strawhat's doctor. A reindeer who ate the Human-Human Fruit (yes, their doctor is a reindeer) and is able to talk with humans. Innocent, naive, and the token cute mascot of the show. Though he's in his tiny cute form most of the time, his use of the Rumble Ball, which allows him to take seven different forms, makes him a fierce fighter. His dream is to cure all diseases.
Nico Robin - An archaeologist and former subordinate of Sir Crocodile, she is the most recent member of the Strawhat crew. She at the Bloom-Bloom Fruit, which allows her to sprout any part of her body anywhere (yeah, it's weird). Not much is known about her at this point in the story aside from that she's clever, reserved, appears to have a jaded past of some sort, and has a keen interest in the Poneglyphs and the "true history" of the world.
Vivi - The Princess of Alabasta who was traveling with the Strawhats for a while. Luffy and co. helped her vanquish the Warlord Crocodile who had planned to take over her country. Though she was granted the opportunity to join the Strawhats permanently, she decided to stay behind and look after her country.
Red-Haired Shanks - Luffy's childhood idol who inspired him to become a pirate. He lost his arm saving Luffy, but has since become one of the greatest and well-known pirates in the world.
Whitebeard -The so-called "Strongest Man in the World," and captain of the Whitebeard Pirates. He is the man closest to finding One Piece and the only one to ever fight Gold Roger to a draw.
Blackbeard - A former subordinate of Whitebeard who went rogue after killing one of his crewmates. He has since gathered his own pirate crew and apparently strives to become a Warlord.
Portgas D. Ace - Luffy's brother and commander of the 2nd division of the Whitebeard Pirates. He is currently hunting Blackbeard on Whitebeard's orders to take vengeance for the crewmate he killed.
Smoker - A stern, but good-natured marine who is constantly hunting Luffy and his crew.
Alvida/Morgan - At the start of his adventure, Luffy meets a young boy named Coby who is unwillingly serving the evil Lady Pirate Alvida. Luffy promptly dispense of Alvida and Coby joins him. They then arrive at a town that is under the rule of the tyrannical Marine, Captain Morgan and his son Helmeppo. They hear about the pirate hunter Roronoa Zoro who has been taken captive by Morgan. Luffy defeats Morgan and Helmeppo and, in return for freeing him, Zoro joins Luffy's crew. Coby stays behind to pursue his dream of becoming a Marine.
Buggy - Luffy and Zoro arrive at a town that has been taken over by the pirate Buggy the Clown. They also encounter a thief named Nami who robs pirates. It is also revealed that Buggy was a former crewmate of Shanks and the two are lifelong rivals. Buggy is swiftly defeated by Luffy and Nami joins Luffy's group, for the time being at least.
Kuro - Luffy and co. arrive at a town where they meet Usopp, the localy lying trouble-maker. They also meet a girl named Kaya, who is the inheritor of her late parents' great fortune. The crew discovers a plot by Kuro, Kaya's butler, who is in fact a pirate, to kill her and steal her fortune. Luffy and co. put a stop to his plan, and in repayment, Kaya gives the Strawhats their ship, the Going Merry. Usopp joins the crew.
Baratie - Luffy and co. arrive at the Baratie, a restaurant on the sea, run by Chef Zeff and Sous-chef Sanji. The Baratie is then attacked by the Pirate Captain Don Krieg who wants to take over the restaurant. They also encounter Hawkeye Mihawk, the strongest swordsman in the world and one of the Seven Warlords. Zoro challenges him, but, predictably, he is easily defeated. To make matters worse, Nami steals the Going Merry and abandons the Strawhats. Zoro and Usopp pursue her. All that aside, Luffy defeats Krieg and Sanji joins the Strawhat crew.
Arlong - The Strawhats track down Nami, who has returned to her home town of Cocoyashi Village, which has been taken over by a gang of Fishmen Pirates led by the human-hating Arlong. It turns out Nami has been stealing from pirates to gather enough money to buy back the village from Arlong, but of course he has no intention of honoring that agreement. The Strawhats vanquish the fishmen and Nami joins the crew (for real this time).
Loguetown - The Strawhats arrive at Loguetown, the town where Gold Roger was born and where he was executed. This is where they first encounter Smoker and mysterious man named Dragon. After a brief scuffle with the Marines and an unpleasant reunion with Buggy, the Strawhats head to the Grand Line.
Laboon - As the Strawhats enter the Grand Line, their first encounter is with a giant whale named Laboon who longs to reunite with a crew of pirates he befriended long ago, but who have, tragically, long since perished. Luffy makes a new promise with Laboon to see him again once he has sailed around the Grand Line.
Whiskey Peak - The Strawhats arrive at Whiskey Peak, an island that at first seems hospitable, but turns out to be inhabited by bounty hunters and the nefarious Baroque Works; an organization planning to take over the country of Alabasta. The Strawhats take Vivi, who was working undercover in Baroque Works, with them on their ship.
Little Garden - The Strawhats arrive at an island called Little Garden, which is inhabited by two feuding giants. Baroque Works agent Mr. 3 also shows up, planning to capture and/or kill the Strawhats and the giants for their bounty. The Strawhats, of course, defeat him.
Drum Island - When Nami falls ill, the Strawhats must stop at Drum Island to find a doctor. There, they meet Chopper, the unlikely reindeer doctor. Unfortunately, they also encounter Wapol, the wicked king who abandoned his country and is now back to reclaim it. Luffy disposes of the corrupt king and Chopper joins the crew.
Alabasta - The Strawhats finally arrive in Alabasta to put a stop to Baroque Works. After a long and arduous journey across the desert country, the Strawhats face off against Baroque Works, led by the Warlord Crocodile, all while trying to prevent a war and a literal ticking time bomb that threatens to destroy the country. The Strawhats are victorious. Vivi stays behind and Nico Robin, a former Baroque Works agent, joins the crew.
Jaya - The Strawhats Log Pose points up, which seems to indicate they must go to an island in the sky. They arrive at Jaya, where they meet Montblanc Cricket, a man who can help them reach the sky island, Skypiea. After Luffy trounces Bellamy, a roughneck pirate who beat up Cricket, the Strawhats ride the "Knock-up Stream" to Skypiea. The Strawhats also encounter Blackbeard for the first time.
Skypiea - The Strawhats arrive at the legendary Skypiea, which has been taken over by the ruthless "God" Eneru. There is also a bitter feud going on for control of "Vearth," the so-called "Holy Land" of Skypiea, between the sky people and the Shandians, the original inhabitants of Vearth. It all culminates in an all-out brawl amongst the Shandians, Eneru's soldiers, and the Strawhats, after which Eneru enacts his plan to destroy Skypiea. Luffy thwarts Eneru's plan and peace is brought to Skypiea.