One Piece Movie 07: Karakuri-jou no Mecha Kyohei
English name: One Piece: The Giant Mechanical Soldier of Karakuri Castle
Genres: Action, Adventure, Fantasy
Type: Movie, Episodes: 1
Aired: Mar 4, 2006
Studio: Toei Animation
Source: Manga
Rating: PG-13 - Teens 13 or older
Synopsis:
The Straw Hat crew salvages a treasure chest from a sinking wreck, inside which they find an old lady. To get the pirates to take her home, she promises them the treasure of a golden crown on her island: Mecha Island. Upon arrival, the crew is attacked by the lord of the island but he has a change of heart and decides to seek their help to solve the mystery of the Golden Crown.

(Source: ANN, edited)