In the 17th century privateer Bart Paxton is commissioned by Charles II of England to capture the villainous pirate Henry Morgan, who has been spiriting English cargoes to his hideout on the island of Tortuga, near Jamaica. Once at sea, Paxton is enraged to discover that Meg Graham, a Gypsy guttersnipe he once rescued from a lecherous butcher, has stowed away on his ship. The young woman charms three of Paxton's officers into teaching her how to act like a lady, and, when the vessel docks in Jamaica, she manages to pass herself off as a noblewoman, fooling even the governor himself. Paxton makes contact with Morgan, offers him a chest of gold in partnership, and lures him into revealing information about his pirate headquarters at Tortuga. When Paxton attacks, however, Morgan is waiting for him and the two men engage in single combat. But they are both knocked into unconsciousness and taken prisoners by the governor when Morgan's pirate arsenal explodes. At their trial, Morgan accuses Paxton of being a fellow pirate, but Meg wins an acquittal for Paxton by revealing her true identity and convincing the governor that Paxton is in the employ of King Charles ...