Baron Omatsuri and the Secret Island is the sixth animated feature film of the franchise. It premiered in Japan on March 5, 2005 and was released to DVD on July 21, 2005. The film made a six weeks run in the Top 10 of the Japanese box office. It made a third place in its first week of showing, a fourth place in its second week, followed by two sixed places, a fifth place in its fifth week, and a seventh place in the sixth week. In Japan it earned at total of 1,200,000,000 Japanese yen, according to the Motion Picture Producers Association of Japan and 10,466,247 US dollar, according to Box Office Mojo.  Internationally, it earned 10,494,545 US dollar.

Having recovered a treasure chest from a sinking ship, the Straw Hat Pirates can’t wait to see what riches await them inside. So imagine their surprise when they find they’ve gotten an old lady instead! Anxious to get back home (and avoid Nami’s wrath for having thrown out the treasure previously in the chest), the old lady offers a great treasure reward if the crew will return her to her home on Mecha Island. Her legend of the Golden Crown sounds too good to be true… but Luffy smells adventure, so what’s the crew to do? In an island full of amazing inventions, the crew will test their riddle-solving skills – and Luffy’s dumb luck – to solve the mystery of Mecha Island and its treasure.

During a raging storm, the crew searches a wrecked pirate ship for any treasure only to find a single chest. On the Going Merry, they open it only to find an old woman who hid there to escape the storm. As they contemplate what to do with her, even suggesting to put her back in the box, the woman tells them about a legendary Golden Crown on her island that she will let them have if they return her there. Though the rest of the crew thinks this sounds suspicious, Luffy agrees. As it turns out, it is impossible to reach using a Log Pose, requiring the use of a “Kame Pose”, which uses a small turtle that always points to the island…