The story of the Hand Island no Bouken special is set a little before the events of One Piece Film Z and depicts a major "Hand Island" incident during the New World storyline. The story is set at "Cannon Town" where a parent and a child work as craftspeople. The incident revolves around them and a commodore of a marine base. The special will also have a flashback scene to the story in the first chapter of the manga, but with new animation. (Source: ANN)

The story arcs aboard the Straw Hat Crew's first ship Going Merry (Merry Go in some adaptations) are recreated with brand-new animation, from Luffy and Usopp's fight and Robin's disappearance to the crew's final farewell to the ship. Going Merry is treated as another member of the Straw Hats as Luffy, Zoro, Nami, and the rest of the crew set sail for the legendary treasure, the One Piece. (Source: ANN)

After suffering great personal loss during the battle of Marineford, Monkey D. Luffy finds himself stranded on Rusukaina, a treacherous island crawling with huge and dangerous creatures. There, he has committed himself to a two-year stretch of training to learn "Haki," the energy that combatants can use to grant themselves a variety of abilities in battle. Luffy is jerked away from his otherwise peaceful training by the abduction of Sandersonia and Marigold, sisters of his friend and ally Boa Hancock. With Boa's aid, Luffy seeks to track down the infamous pirate responsible for the kidnapping, a man whose recent prison break is the result of Luffy's own reckless actions. Luffy must use his developing grasp of Haki to defeat this new foe while coming to terms with his overbearing grief in the process. [Written by MAL Rewrite]

The special will revisit the childhood past of the three sworn brothers Luffy, Ace, and Sabo, when they all dreamed of becoming pirates. In addition, it will depict how Sabo originally came into the kingdom of Dressrosa (which was not depicted in Eiichiro Oda's original manga or the television anime), as well as his reunion with Luffy from his point of view.