This movie is "One Piece: Romance Dawn Story" and story line : The Straw Hat Pirates send Luffy to look for food in the Mini Merry II, only for Luffy to get lost and deviate from the path. Then he meets Galley's ship, a pirate. Meanwhile on an island, they realize that Galley's pirate ship is approaching, and a young girl named Silk decides to fight to protect her treasure..