Nami stumbles upon a map of the island of rare beasts, where it is said to contain priceless treasures, and the Straw Hat Pirates decide to advance to the island despite Chopper's resistance. At this moment, an undersea volcano erupted, throwing the Golden Melly into the air. By chance, they were thrown to Treasure Beast Island. The island is ruled by human-speaking animals, whose old king, the unicorn lion, has passed away, and Chopper, who has stumbled upon it, is worshipped as the new king by the beasts. Chopper can't resist the beasts, and he has the right to serve. While the island of Rare Beasts rejoices at the birth of a new king, the greedy and evil Count Batra and his minions land on the island. For the sake of the legendary "King's Treasure", he did not hesitate to kill the animals on the island. They are bound to clash with the Straw Hat Pirates......　　This film is based on the original book of the same name by Japanese manga artist Eiichiro Oda, and is the third animated theatrical version released in 2002.