WARNING: CONTAINS SPOILERS!

Kit Gerado (Sterling Haydon) is a French privateer who calls himself the “Golden Hawk.” While stranded on Basse-Terre Island with his crew, they get word of a ship the Garza captained by Luis del Toro, who Kit believes killed his mother. Because Kit has lost his ship, he has a duel with the captain of the Sea Flower and uses the Sea Flower to attack del Toro’s ship.

During the fighting, a young woman (Rhonda Fleming) being held prisoner aboard the Garza jumps overboard to escape and is rescued by Kit. She tells Kit she is a Dutch maid named Jane Van Corte, but really she is a pirate who calls herself Captain Rouge. Kit gives her his pistol and lets her sleep in his cabin, hoping to seduce her, but when he tries to enter the cabin she shoots him, and escapes by jumping overboard and swimming to a nearby island.

Meanwhile, Kit continues to attack Spanish ships, eventually taking Bianca del Valdiva (Helena Carter) and her maid as prisoners. The maid explains that Bianca is engaged to marry del Toro and is on her way to Cartagena to marry him. Kit plans to ransom her to del Toro for 10,000 gold crowns. They send the ransom letter to del Toro, telling him to meet them on the island of Cul de Sac. When del Toro (John Sutton) arrives with the gold, Kit confronts him with killing his mother Jeanne Boullin. Del Toro admits knowing his mother but denies killing her and swords are drawn, but del Toro reminds them he was guaranteed safe conduct. Del Toro leaves with Bianca.

As Kit is preparing his ship to leave, they are suddenly surrounded by three Spanish ships led by Del Toro. Seeing he is outnumbered, Kit waits until nightfall and maneuvers a raft filled with gunpowder against one of the ships and blows it up. With one ship out of commission, the Sea Flower attempts to flee but is intercepted by an English ship the Witch and captured. Kit is due to be hanged, however, Captain Rouge, captain of The Witch, intervenes on his behalf and takes half of the ransom money for herself.

Kit and his crew must return to Sainte Domingue to rearm the Sea Flower. While they are there, they are informed that the French are planning an attack on Cartagena, and they are given orders to make raids on Jamaican plantations to prevent English ships from getting supplies there and helping the Spanish. While making the raids, Kit’s men accidentally set fire to Rouge’s plantation. Kit learns that Rouge is actually Lady Jane Golphin whose lands were taken illegally during the war. She became a pirate to get the money to rebuild. He offers to help her, telling her he loves her, but she sends him away swearing vengeance on him.

Having been rejected by Rouge, Kit decides to go to Bianca and tell her he loves her. He wants her to help him kill del Toro and destroy Cartagena. Bianca sees through his ploy and turns him in and he is arrested. Later when Bianca confronts del Toro as to why he will not hang Kit, he confesses to her that Kit is his son, and his mother died in an accident, but Kit doesn’t know the truth. At the trial, del Toro tries to dismiss the charges, but Rouge breaks in and tells the court that Kit’s men are responsible for the attacks on Jamaica. The tribunal votes for them to hang.

On the night before the hanging, Bianca persuades Rouge to help Kit, getting her to admit that she really loves him. Disguised as a man, Rouge pretends to be the hangman’s assistant who needs to measure Kit for the rope. In her toolbox, she hides a gun and helps them escape. Kit refuses to return to his ship, insisting that he must kill del Toro. Rouge helps Kit get inside the fortress. The French ships attack but have a hard time destroying the fort as the fort’s cannons blow up many of the ships. Kit Gerado blows up the powder magazine in the fort’s armory which brings down the fort. Del Toro is shot, but Bianca reveals the truth to Kit, andfather and son are reunited. They sail away, and Rouge and Kit reunite and kiss in the Sea Flower’s cabin.