Baron Omatsuri and the Secret Island

Released in 2005 as the franchise's sixth theatrical film, this 91-minute feature was helmed by Mamoru Hosoda and written by Masahiro Itō. Its premise is deceptively cheerful: a message in a bottle lures the Straw Hats to Omatsuri Island, advertised as a paradise of spas, fine food, and welcome for strong pirates. Luffy, eager to prove his crew are pirates of the highest order, accepts on the spot. What begins as a holiday quickly curdles, as the island's smiling Baron sets a series of cruel games that pry the crew apart one bond at a time, while Robin chases the mystery of the island's strange flower, the Lily Carnation.

The crew arrives to find a dazzling resort run by Baron Omatsuri, a hulking man with a tiny talking flower on his shoulder. He invites them into a competition styled after the Davy Back Fight, beginning with a goldfish-catching contest against a monstrous armored fish. The Straw Hats narrowly win thanks to Chopper, which only infuriates the Baron into demanding more rounds. A ring-toss race through the canals follows, where the team's quarrels with one another start to fester even as they scrape out a victory.

Wandering the island, Chopper meets a frightened pirate family and uncovers rows of tombstones, while Luffy encounters Brief, a lone captain who warns that the Baron exists to shatter crews. Brief reveals that the Baron once led the Red Arrows Pirates and that the island's residents do not age, sustained by something sinister. As trust among the Straw Hats collapses under the games, the crew members vanish one by one, drawn into the Lily Carnation, a flower of false reincarnation that devours people to keep the Baron's long-dead friends alive in stasis.

Stripped of his entire crew before his eyes, a broken Luffy is dug out and tended by Brief and the pirate family, whose daughter Daisy can hear the trapped Straw Hats still calling for him. Refusing to surrender, Luffy fights through a storm of arrows to reach the Baron. When the flower reveals its true monstrous form built from his absorbed friends, it is the cowardly Papa who finds the courage to fire the Baron's own bow, blasting the Lily Carnation apart. With the flower destroyed, the absorbed crew is restored, and Luffy lands a final punch as the Baron at last makes peace with the friends he lost. The Straw Hats wake unharmed, remembering nothing, and reunite beneath the rising sun.

The film opened third at the Japanese box office in its first week, behind Lorelei and Shark Tale, before slipping to fourth the following week. It drew notably mixed reactions for its departure from the series' usual look, with shading and artwork frequently likened to the second Digimon movie, and many sequences leaning on computer-generated imagery to heighten the visuals. A trailer placed Buggy and Bentham among the theater audience despite their absence from the story, and Chopper's Guard Point form was drawn far larger here than in the contemporaneous anime.