During the Franco-Spanish War in the 16th century, the Sultan of Morocco condemns to death his favorite general, Barbarossa, because the pirate flirted with the newest fiancée in the Sultan’s harem. Barbarossa, who is also known as “Redbeard,” escapes to a ship off the coast of Tangiers where he incites the slaves to rise up against the ship’s captain and crew. Barbarossa then takes over as captain, promising the slaves freedom and wealth in exchange for their labor. Although all of the previous crew are thrown overboard, the newly freed slaves discover the first mate, Renzo, hiding below deck. Renzo claims to have formerly been a Spanish captain who was dismissed for theft, and now pledges his loyalty to Barbarossa. After receiving a French commission as a privateer, Barbarossa sails to Tortuga, where the governor’s representative, Capt. Romero, anticipates purchasing the “slaves” as arranged by the ship’s original captain. Unknown to Romero, the men are loosely chained to allow an easy escape after Barbarossa collects the payment. Inside the governor’s fortress, Barbarossa flirts with the governor’s daughter, Countess Alida, but she rebuffs him, and later proves her mettle as a tough negotiator when she arrests Barbarossa for refusing to turn over the slaves. At a nod from Alida, Romero slaps the pirate twice for his insolence, prompting Barbaraosa to release the slaves. However, Barbarossa’s elderly navigator, Peg Leg, whistles a signal for the men to free themselves. They then liberate the governor’s prisoners and capture his guards, except for Romero, who escapes. Barbarossa takes Alida hostage, after which a young boy named Datu, the self-appointed spokesman for the prisoners, suggests that Barbarossa scout the Bay of Santa Maria for Spanish ships to appropriate so the freed men can sail with him. In the palace of the Governor-General of Havana, Alida’s fiancé, Spanish Capt. Jose Salcedo, argues with Capt. Goiti about the best way to rescue Alida. Although Goiti urges the governor to pay the ransom Barbarossa demands, the governor instead agrees to Salcedo’s plan to pit the fleet against the pirate. Barbarossa takes the Spanish ships at Santa Maria, imprisons the mayor, and engages in a battle of wills with his hostage, Alida. Alida attempts to escape during a celebration but is captured by Renzo, who reports that Salcedo’s fleet has arrived in Tortuga. Barbarossa, who has fallen in love with Alida, doubts Salcedo’s honor, and raises her ransom to challenge her fiance. Salcedo’s efforts are unsuccessful and he returns to Havana, where Barbarossa poses as an old peasant commissioned by the pirate to bring Salcedo to a hostage exchange site. Once there, however, Salcedo, whose marriage to Alida was arranged, refuses to turn over the ransom money, despite her protests. Barbarossa then proves Salcedo’s insincerity after he drastically reduces his ransom demand and Salcedo still refuses to pay. When Salcedo threatens to harm the pirate if he should encounter him, Barbarossa drops his disguise and swiftly disarms Salcedo in a duel. While they are fighting, Alida scrawls the name of the pirates’ next anchorage in the dirt. Barbarossa then takes the gold and Alida and leaves Salcedo tied to a tree. Barbarossa and his vast crew later set up camp at Windward Bay, but while they are away attacking Spanish galleons, the women and children left behind at camp are massacred. An injured Datu informs Barbarossa that Salcedo was behind the attack, and the pirate vows revenge. In Havana, a new governor-general promotes Goiti over Salcedo because of his failure to capture the pirate. Some time later, Barbarossa presides over a group wedding for his crew members. During the festivities, Alida taunts him by dancing with his crew and kissing Renzo. In a rage, Barbarossa strikes his first mate. Shortly afterward, Peg Leg advises Barbarossa that Alida will never love him as long as she is a hostage, and suggests that the pirate return the ransom to her. After Barbarossa consents, Peg Leg takes the gold coins to Alida. However, she has already escaped with the help of Renzo, who murders the old man, steals the gold and plants Alida’s pearls in Peg Leg’s hand. Barbarossa, assuming that Alida murdered his loyal friend, plans to attack Havana, Alida’s presumed destination. After his fleet lands nearby, Renzo escapes to warn Salcedo of the imminent attack and pinpoints their hiding place in North Bay, in hopes of reinstating his Spanish commission. When Salcedo refuses him any reward, Renzo confesses to Alida that he stole the gold and murdered Peg Leg. In desperation, Renzo now offers to return the ransom, but Salcedo murders him in cold blood. Goiti later mocks Salcedo’s plan to once again confront Barbarossa, but allows him to use the Spanish fleet to mount the attack. Barbarossa and his men mount a fierce attack in Havana, during which Datu saves Barbarossa’s life by killing Goiti with a sword. When Alida hears the cannons fire as a carriage takes her and Salcedo’s mother away from the city, she escapes and returns to Havana to warn Barbarossa of Renzo’s betrayal. Barbarossa and his fighters return to North Bay with their cannons, and arrive in time to witness Salcedo’s troops destroying their ships. Fortified by Alida’s devotion, Barbarossa rallies his people and together, they outwit Salcedo’s patrol and steal the Spanish fleet. Salcedo is arrested and Barbarossa and his crew set sail for North America and freedom.