As the Straw Hat Pirates sail through the Grand Line, a sudden eruption of geysers beneath the Going Merry sends the crew flying over a nearby island. In the chaos, Chopper falls overboard and becomes separated from his friends. While Luffy and the others land on the far side of the island, Chopper finds himself hailed as the new king by the local animals. However, danger looms as a group of human “horn hunters” arrives. Their leader, Count Butler, is a violin-playing man who consumes horns to gain strength, and he seeks to devour the island’s greatest treasure to inherit immense power. Can Luffy and the crew stop Count Butler’s scheme and save the island? And will they be able to show Momambi that not all pirates are the villains he believes them to be?