In a world mystical, there have a mystical fruit whom eat will have a special power but also have greatest weakness. Monkey ate Gum-Gum Fruit which gave him a strange power but he can NEVER swim. And this weakness made his dream become a sea – robber to find ultimate treasure is difficult. But along his ways, he meet himself many members to help. Together, they sail the Seven Seas of adventure in search of the elusive treasure One Piece.