One Piece: Fish-Man Island Saga is a retouched and condensed version of the One Piece anime adaptation of the Fish-Man Island Saga.

The Scribble Kingdom in the sky which charges it's life energy with scribbling is endangered when the people in the world lessen their scribbling. The military is send in to enforce more scribbling.

Shin-chan and the Kasukabe Defense Group are planning to perform an absolutely no-stunt Kung Fu challenge on the stage in Aiya Town, also known as the Chinatown of Kasukabe city.

Sixteen years ago, a mysterious masked ninja unleashes a powerful creature known as the Nine-Tailed Demon Fox on the Hidden Leaf Village Konoha, killing many people. In response, the Fourth Hokage Minato Namikaze and his wife Kushina Uzumaki, the Demon Fox's living prison or Jinch?riki, manage to seal the creature inside their newborn son Naruto Uzumaki. With the Tailed Beast sealed, things continued as normal. However, in the present day, peace ended when a group of ninja called the Akatsuki attack Konoha under the guidance of Tobi, the mysterious masked man behind Fox's rampage years ago who intends on executing his plan to rule the world by shrouding it in illusions.

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.