One Piece is a popular shonen manga written by Eiichiro Oda. The manga has been published in weekly chapters since 1997 while the anime has been airing since 1999. The manga has over 600 chapters and the anime has over 500 episodes. Both of them are still ongoing. One Piece is the best selling manga in Japan. Funimation is currently dubbing the anime in English and the subbed versions are on Funimation's One Piece Official website.
20 years before the start of the main storyline, the King of the Pirates Gol D. Roger, also known as Gold Roger, was executed by the marines. He gained wealth and fortune. The Pirate King was the only one to sail all of the seas. Before his execution on the scaffold, he let the world know that his treasure, the One Piece, is at the end of a dangerous ocean called the Grand Line. His execution and his hidden treasure started a great age of piracy.
8 year later, Monkey D. Luffy is an 8 year old boy that wants to be a great pirate like his pirate idol Red-Haired Shanks. When Shanks and his crew come into Luffy's village, Luffy accidentally eats a Devil Fruit that the crew is carrying. The Devil Fruit is called the Gum-Gum Fruit which gives Luffy the ability to stretch like rubber at the cost of never being able to swim again. When a mountain bandit throws Luffy into the ocean to be eaten by a sea monster called a Sea Beast, Shanks saves Luffy but loses his arm in the process. Shanks gives Luffy his straw hat and tells him to give it back to him when he becomes a great pirate.
Luffy's grandpa and marine hero Monkey D. Garp puts Luffy in the care of a female mountain bandit by the name of Curly Dadan. Portgas D. Ace, who is a little bit older than Luffy is also under Dadan's care. Ace doesn't like Luffy at first, but they end up becoming like brothers. Luffy sets sail after Ace at 16 years of age and gets together a crew of 8 other pirates throughout the series called the Straw Hat Pirates. Luffy set sail to become the King of the Pirates.
The swordsman is Zoro who dreams of becoming the world's greatest swordsman. The navigator is Nami who dreams of mapping the entire world. The sniper is Usopp who dreams of becoming a brave warrior of the sea. The cook is Sanji who dreams of finding the All Blue which is a cook's paradise with all of the world's fish. The doctor is the human reindeer Chopper who dreams of becoming a great doctor in honor of his dead friend. The archaeologist Robin dreams of finding out about the hundred year void which might have been covered up by the marines. The cyborg/human shipwright Franky dreams of sailing the world's oceans on a great ship of his own making. The living skeleton musician Brook dreams of becoming reunited with his whale friend Laboon after going on a big adventure.
On their adventures, they deal with marines and other pirates in order to pursue their dreams. The manga is rated T and the anime is rated TV-14.