One Piece: Giant Mecha Soldier of Karakuri Castle (2006) is a Animation, Adventure, Action, Comedy, Science Fiction, Fantasy film that follows the Straw Hats visits an island, known as Mecha Island, where a fisherman sings an old folk song about a Golden Crown. Searching for that mysterious treasure, they find a hidden entrance into the island. The island's leader, Ratchet, impressed with the find and in search of the Golden Crown himself, invites the crew to join him in his search and the crew along with Ratchet and his henchmen enter the cave. As it turns out, the islands true form, is that of a giant turtle. Ratchet, who had known this all along, uses his mechanical castle to take control of the turtle, in order to use it, to take over the world. Now the Straw Hats have to stop not only Ratchet, but also the helpless turtle, from crashing into a nearby island. One Piece: Giant Mecha Soldier of Karakuri Castle is not currently listed with streaming providers in your selected region, but availability can change over time. It has a user rating of 7.0 out of 10 from 185 votes. Fans of animation movies may also want to explore similar titles below.