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.

The movie is a retelling of the Drum Island arc with new music and animation. Vivi has been removed from the plot while both Nico Robin and Franky, who joined the crew after the Drum Island arc, have been added. The movie also has the Straw Hat's new ship, the Thousand Sunny. It has been stated that Oda will be creating a new character for this movie, Wapol's older brother, Mushul, who also appears to be a Devil Fruit user. 

(Source: Wikipedia)

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]

The Straw Hat Pirates enter the rough seas of the New World in search of the hidden treasures of the Pirate King, Gol D. Roger－One Piece. On their voyage, the pirates come across a terrifying, powerful man, former Marine Admiral Z.

Z is accused of having stolen the "Dyna Stones", weapons believed to have the power to shake up the New World. The Marine Headquarters believes Z is about to use it to end the pirate era, and with it, the lives of many innocent people. In fear of such a phenomenal event, marines start to take action against the former admiral.

Even if it means stumbling upon marines and the navy, the Straw Hat Pirates decided to chase after Z and stop him from causing havoc. As they continue to embark on their ventures, the pirates bump into new and familiar acquaintances.