The special takes place during the two year before the Straw Hats reunite on Sabody. Luffy is currently in Rusukaina training to get stronger to take on the New World. However the training is interrupted when Hancock's sisters, Marigold and Sandersonia, are kidnapped by the Byrnndi World, a pirate who was locked away on Level 6 of Impel Down but escaped during Luffy's invasion to save Ace, in order to lure Hancock to him and use her as a hostage against the World Government due to her Shichibukai status. Thus Luffy and Hancock head off to confront him and save Hancock's sisters.

Red panda Retsuko, worked to the bone, unleashes her frustration in the form of death metal. Lately, though, she's found another joy—getting the most likes possible on her Instagram posts. In fact, it is said that social media attention can release endorphins. As Christmas falls upon the city, Retsuko's hunger for validation only grows, pushing her to find new ways to embellish and sugarcoat her otherwise drab life for the internet to see.

Lupin has invited all of his friends to a villa on a private island. It's the first time they've seen each other for the past five years. Lupin is planning a big surprise while they are all at the villa except Fujiko, Goemon and Jigen find Lupin's behavior to be unusual. They are also curious about who the man in the iron mask is, who is chained up to a wall for the reasons they are about to find out.