Amazon Lily Arc

Flung across the ocean by Bartholomew Kuma's power after the Straw Hats' rout at Sabaody Archipelago, Luffy crashes onto Amazon Lily, a Calm Belt island populated entirely by the Kuja, a tribe of fighting women who kill any man on sight. Cut off from his crew and desperate to return, he stumbles into a culture that has never seen a male, then into a confrontation with its ruler. The arc carries weight far beyond Luffy's predicament, since it reveals the date of Portgas D. Ace's execution and sets him on the path toward Impel Down. It also formally introduces Haki and shows where each scattered Straw Hat has landed.

After days adrift in the air, Luffy slams down on the island and tries to navigate home using his Vivre Card. He is found unconscious and overgrown with parasitic mushrooms by three Kuja warriors, Marguerite, Sweet Pea, and Aphelandra, who haul him back to their village. The women initially mistake him for one of their own until their elder, Nyon, identifies him as a man, throwing the settlement into panic and landing Luffy in a cell. He escapes by grabbing Marguerite, who holds his Vivre Card, and the two get acquainted in the jungle while she explains that the empress, Boa Hancock, is a pirate revered by all.

Out in the Calm Belt, Vice Admiral Momonga delivers the World Government's summons to Hancock, a Warlord of the Sea, ordering her to join the coming war against Whitebeard. She refuses outright, petrifying his crew with her Mero Mero no Mi before he escapes by stabbing his own hand. Returning to a hero's welcome, Hancock displays her cruelty, while a guarded daily ritual conceals the mark on her and her sisters' backs, explained to outsiders as a Gorgon's curse. Luffy, blundering through the castle in search of a boat, crashes into Hancock's bath, sees the mark, and proves immune to her powers. Captured and dragged to the arena for execution, he watches her petrify Marguerite and her friends for aiding him.

Forced to fight Hancock's snake-formed sisters Sandersonia and Marigold, Luffy realizes their attacks can now hurt him. When they threaten to smash Marguerite's statue, he unleashes Supreme King Haki, stunning the crowd, then enters Gear 2 and overwhelms both sisters. He deliberately shields Sandersonia's exposed back from the crowd, understanding that the secret mark has nothing to do with their duel, which moves Hancock to tears. Afterward she chooses to restore Marguerite and the others when Luffy values their lives over his own escape. Privately, prompted by Nyon and by news of Luffy striking a World Noble, Hancock confesses her past: enslaved by the Celestial Dragons at twelve, branded as less than human, freed years later by Fisher Tiger's raid on Mary Geoise, and ashamed enough to invent the Gorgon lie. Luffy's defiance of the same oppressors wins her over completely.

Learning that Ace is to be executed, Luffy abandons his plan to find his crew and resolves to reach Impel Down, which requires Hancock to obey the government summons that gives him fast passage on a Marine ship. Hancock, stricken by Love Sickness after falling for Luffy, agrees, saving both herself and her island's treaty. Hidden beneath her clothing, Luffy boards Momonga's vessel bound for Impel Down. Meanwhile the arc reveals where Kuma sent the other Straw Hats, from Nami on the sky island Weatheria to Robin enslaved at Tequila Wolf, Zoro encountering Perona on Kuraigana Island, and the rest scattered across distant lands.

Hancock stands as the seventh and final Warlord of the Sea introduced before the time skip, and the arc formally establishes Haki, including the rare Supreme King variant held by both Luffy and Hancock. Her tragic history as a former Celestial Dragon slave is laid bare, along with Fisher Tiger's founding of the Sun Pirates and his erasure of slave brands with the sun symbol, threads that pay off in the Fish-Man Island Arc. Hancock's affection for Luffy spares her from the fatal Love Sickness that killed earlier empresses and commits her to aiding him repeatedly in the arcs ahead. Most importantly, Luffy's discovery of Ace's fate drives him straight into the Impel Down Arc, while the revealed locations of his crewmates set up their individual two-year journeys.