The series begins with the execution of Gol D. Roger, a man known as the King of the Pirates (海賊王 Kaizokuō?). Just before his death, Roger announces that his treasure, the One Piece (ひとつなぎの大秘宝 (ワンピース) Wan Pīsu?), will be available to anyone who finds it, beginning the Great Pirate Era (大海賊時代 Daikaizokujidai?). As a result, countless pirates set out to the Grand Line to look for the treasure.

Luffy, then meets Captain Smoker, a Navy captain who can turn into smoke. He briefly captures Luffy, but Luffy is saved by his father, Monkey D. Dragon, who is identified by Smoker simply as Dragon, the most wanted man in the world. After making their way into the Grand Line, the group meets Nefeltari Vivi, a princess who wants to help save her country, the Alabasta Kingdom, from the crime syndicate Baroque Works. They later befriend the doctor and anthropomorphized reindeer Tony Tony Chopper while in Drum Island.