U.A. High School's students of Class 1-A have made it to summer break. Izuku Midoriya accompanies his mentor All Might to a celebratory superhero festival on I-Island, an isolated patch of land dedicated to researching Quirks and everything else associated with the hero business. Midoriya is granted the opportunity to meet All Might's friend Dave and Dave's daughter Melissa, two talented hero equipment engineers. He also encounters his classmates, most of whom have been given the opportunity to spend part of their summer break at the festival.

However, a mysterious squad of villains infiltrates I-Island, and it is up to Midoriya and his friends to confront them, using their developing Quirks to fight off the new enemy and uncover a treacherous plot.

[Written by MAL Rewrite]

Izuku "Deku'' Midoriya and his fellow students in Class 1-A of UA High's hero course have been chosen to participate in a safety program on Nabu Island. To further improve their skills and gain experience in more ordinary heroics, the students aid the kind citizens with small services and everyday chores. With the low crime rate in the quiet community, all seems well and good, but the rise of a new villain threatens to put the students' courage to the test and challenge their capabilities as heroes.

A merciless villain by the name of Nine is in search of a certain "quirk" needed to fulfill his diabolical plan—creating a society where only those with the strongest quirks reign supreme. As his attack on Nabu Island endangers the lives of the residents, securing the citizens becomes the first priority for Class 1-A; defeating Nine along with his wicked accomplices is also imperative. A straightforward strategy is formulated until a young boy named Katsuma Shimano, whom Deku had befriended, suddenly requires particular protection. Concerned for the boy's wellbeing, Deku and his classmates must now devise a plan to ensure Katsuma's safety at all costs.

With Nine wreaking havoc to find the catalyst for his ill-intended schemes and the heroes desperate to defend Katsuma from harm, will Deku and his friends be able to come out victorious, or will they find themselves unable to escape a hopeless situation?

[Written by MAL Rewrite]

The film opens with Nefeltari Vivi flying with Pell in a brief flashback. Returning to the present, Vivi and the Straw Hats meet Crocodile's subordinate Mr. 2 Bon Clay. Mr. 2 shows the Straw Hats his devil fruit ability, which allows him to assume the form and voice of anyone whose face he has touched. Vivi describes a brief history on how the Baroque Works leader Crocodile has used Dance Powder while posing as the country's hero. He has also tricked the rebel and royal armies into fighting each other. Once in Alabasta and after crossing the desert, the Straw Hats find the rebel's base deserted, while the rebel army, led by Vivi's childhood friend Koza, witnesses the port town Nanohana being burned by members of Baroque Works disguised as soldiers of the royal army. The rebels decide to attack Alubarna, where at the same time Mr. 2 impersonates the king, Nefeltari Cobra, and orders the royal army to engage. Meanwhile in the desert, the Straw Hats are intercepted by Crocodile and his partner, Ms. All Sunday. Crocodile aims for Vivi, but Luffy stays behind and distracts him, while the other Straw Hats escape. In the ensuing fight, Crocodile defeats Luffy by impaling him through the chest with his hook and buried alive.

Upon hearing news that islands in East Blue are being destroyed, Monkey D. Luffy and his crew go to investigate. On their way, however, an outlandish pirate ship appears out of the sky, helmed by the infamous pirate Shiki "the Golden Lion"—a man who ate the Float-Float Fruit and the first ever prisoner to escape from Impel Down. In his quest to defeat the World Government, Shiki kidnaps Nami to be his own navigator and sends the rest of the Straw Hat Pirates to his floating islands as hostages, leaving her in a dilemma. Separated in a land under Shiki's absolute control, Luffy and his crew must survive the mystifying terrain in order to bring back their navigator and friend.

[Written by MAL Rewrite]