Captain “Bully” Hayes and his crew bring a cargo of rifles to a tribe of South Pacific islanders at war with Spanish colonialists. When the queen refuses to pay for the guns, Hayes suspects treachery and throws his bandolier into a fire, hoping the exploding bullets will frighten the natives. However, the sailors are quickly surrounded, and only Hayes breaks free. After successfully eluding his pursuers, Hayes is arrested by a company of Spanish soldiers, led by his nemesis, Ben Pease. While he waits in his cell to be hanged, Hayes tells his story to writer Louis Beck, who considers him the last of the pirates. Hayes is proud to be called a pirate, but stresses that he always lived by a moral code. He recounts the events leading to this moment, beginning with a voyage on his ship, the Rona, to a small island where passengers Nathaniel “Nate” Williamson of Boston, Massachusetts, and his fiancée, Sophie, are to begin their missionary work. Hayes and Sophie have a mutual attraction, and she invests her small inheritance in his cargo business as a way of maintaining contact. Upon reaching their destination, Nate enjoys a happy reunion with his uncle, Reverend Williamson, and his aunt, Katherine, while Sophie watches wistfully as the ship sails away. The elder Williamsons express their surprise at the couple’s safe arrival, considering Hayes’s reputation as a “cutthroat" and “blackbirder,” or slave trader. The next day, as Rev. Williamson officiates at his nephew’s wedding, a group of blackbirders, led by Pease, invade the island. Nate Williamson is rendered unconscious, while his aunt and uncle are killed, and Sophie is taken prisoner, along with most of the island’s inhabitants. When he regains consciousness, Nate assumes Hayes is the culprit and pursues him on a raft, which capsizes, leaving the young man stranded on a sandbar. On Pease’s ship, the Leonora, the captain meets with Count Von Rittenberg of Germany, who wants to expand his country’s influence in the South Pacific. Pease accepts 5,000 gold marks to broker a deal with King Owatopi of Ponape to establish a German anchorage on the island, but warns Rittenberg that the inhabitants practice incest, cannibalism, and human sacrifice. Elsewhere, Hayes and his crew discover Nate stranded on the sandbar and bring him aboard. Hayes answers Nate’s accusations of murder and blackbirding by identifying the guilty party as Pease, who leaves mark implicating Hayes at scene of his crimes. He explains that the two were once business partners, and during a fight over a woman, he accidentally shot away Pease’s testicles. Hayes offers to assist Nate in his quest to rescue Sophie and kill Pease. They sail to Samoa, where Pease is auctioning his captives into slavery. While Hayes inquires about Pease’s whereabouts, Nate searches for Sophie. He enters the auction house and denounces Pease, after which he is ejected from the building. Upon learning that Hayes is on the island, Pease orders his men back to their ship, but Hayes and his men dispatch each of the crewmembers along the way. Nate boards the Leonora and finds a note from Sophie to Hayes, saying that she is being taken to Ponape, adding that she will always remember him. Nate and Hayes confront Pease, who tries to leave the village on a buckboard. When they demand Sophie’s return, Pease rolls a barrel of human heads toward them and continues toward the beach. Hayes and his crew follow on foot and reach the shore as Pease boards Von Rittenberg��s steam-powered battleship. Realizing they need a faster ship, the men steal the Leonora and sail for Ponape. Inside the captain’s quarters, both Nate and Hayes admit to being in love with Sophie. However, Nate believes Hayes should marry Sophie, as she would be a positive influence, while Hayes argues that Nate would be a better companion for her. They ultimately conclude that Sophie should decide for herself. On Ponape, Pease and Rittenberg are brought before King Owatopi. They offer the king a full-sized human head and a barrel of shrunken heads as payment for use of the island. But Owatopi demands more, so they deliver Sophie as a human sacrifice. As she is lowered into a flaming pit, Nate and Hayes come to Sophie’s rescue, then fire on the natives, killing the king and several of his minions. The adversaries return to their ships, and Rittenberg unsuccessfully attempts to sink the Leonora, before following it into a cove. The pirates board the warship, kill Rittenberg and most of his crew, and place an artillery shell in the gun turret mechanism. As the pirates swim back to their ship, Pease orders the gun operator to aim in their direction, detonating the shell and destroying the warship. Pease survives and swims to shore. Now in his prison cell, Hayes tells Beck that in the eighteen months since the incident, he has become a gunrunner to anti-colonialists, and Nate and Sophie are a married couple living in Boston. Hayes is led to the gallows as Pease looks on with delight. Nate, disguised as a priest, produces two pistols, and he and Hayes fire on the Spaniards. Sophie appears at the top of the prison wall, disguised as a nun, and throws ropes down to the men. She signals a pair of horses outside the wall and they pull the men to the top of the wall. When Pease tries to interfere, Hayes ties one of the ropes around his neck, and as the horses pull, Pease is hanged while Hayes is hoisted over the wall. Upon reaching shore, the three slide down a rope and crash into a guano barge, then board a dinghy and row toward the Leonora.