One night, when the Straw Hat Pirates are asleep in their beds except for Robin, they all dream of a cloaked young boy underwater playing music from a sea horn. In the morning, when Robin wakes her crewmates up, she is shocked to discover that they have no memories of her or them being in a pirate crew. With the memories from before joining the crew still in their heads the crew begins to split up. Now it is up to Robin to not only reunite the crew and help get their memories back, but also find out the cause of their mysterious memory loss. There are many characters in the game. These are the ones which you can battle against and use.