Monkey D. Luffy sets off to become the new Pirate King; Luffy befriends a frightened cabin boy named Koby and promises to help him join the navy; the two boys must fight Lady Alvida, the Pirate Queen.

Luffy and his new companion Coby set sail in search of the infamous pirate hunter Zoro, rumored to be held captive at the Marine Base.

Luffy convinces Zoro to join his crew, but they must first defeat Captain Morgan. After freeing the island from Morgan's oppressive rule, Coby is accepted as a marine while the other two continue on their journey.

Out on the sea, Luffy almost loses his hat and reflects on his past, and how a pirate named Shanks influenced him. Afterwards, Luffy meets Nami, and Buggy the Clown's men.

Luffy rescues Nami but is then betrayed by her when she steals Buggy's map; Buggy threatens to kill Luffy and Nami, but Zolo arrives just in time to rescue them.

Luffy, Nami and Zolo manage to escape Buggy, who sends the Beast Breaker after them to get revenge.