In the vast expanse of the Atlantic Ocean in 1659, the story unfolds around the infamous aging English pirate, Walter Matthau, known as Captain Red, and his young cabin boy, Cris Campion, nicknamed "Frog." The narrative begins with their mishap on a raft, stranded and without supplies, but luck intervenes when they are rescued by a Spanish galleon named Neptune, en route to Spain.
Soon, both Red and Frog find themselves imprisoned in the ship's brig after being accused of poisoning the ship's captain, Ferdy Mayne, Captain Linares, in an alleged attempt to steal a legendary golden throne from the Aztec King Catapec Anahuac, which is secretly stored in the ship's hold. Red becomes increasingly fixated on securing this treasure for himself, fueling his obsession with power and riches. Meanwhile, Frog develops feelings for Maria-Dolores, the niece of Maracaibo's governor, who is traveling as a passenger on the Neptune.
The captain's sudden death thrusts the ship’s authority into the hands of the ambitious first mate, Damien Thomas, Lieutenant Don Alfonso de la Torré. Don Alfonso is also secretly in love with Maria-Dolores, but she does not share his affections, leading to tensions and rivalry. Red and Frog, alongside the crew of Neptune, try to stir a mutiny. Their attempt results in their being sentenced to death, but Red devises a clever plan that incites chaos aboard the ship, giving the rebels a chance to overthrow their captors in an intense mutiny. The crew rallies behind Red, and they successfully take control of the ship.
During this upheaval, Frog rescues Maria-Dolores from an assault and earns her affection, which complicates the brewing conflicts. With Red now in command, the crew heads to a hidden pirate cove on an uncharted island, ruled by Dutch, an old accomplice and merchant, played by Roy Kinnear. Red throws a lively celebration, captures Don Alfonso and his officers, but chaos ensues when Dutch's own men release the prisoners during the festivities. Don Alfonso and his crew later retake the Neptune and sail away with the golden throne.
Red's relentless pursuit leads him to Maracaibo in Gran Colombia (present-day Venezuela), where he devises a daring plan to seize the throne. With Frog and Boomako, Red infiltrates the governor's residence, taking Maria-Dolores hostage to force her wealthy uncle to surrender the treasure. After intimidating the governor, Red obtains a document authorizing him to confiscate the golden throne. However, their efforts are foiled when they fail to move the heavy treasure out of the bay and get captured by Don Alfonso.
In prison,Maria-Dolores confesses her love for Frog, and the two share a tender moment before she returns to Neptune. The ship sets sail for Spain, with Don Alfonso now promoted to captain. Learning of their predicament, Boomako and the pirates launch a daring attack that frees Red and Frog from jail. The climax involves a fierce naval battle where Red sacrifices his ship to sink it, ensuring escape and chaos on the high seas.
In the chaos, Red, Frog, and Boomako manage to escape aboard their own boat, clutching the golden throne. During their escape, Frog finds himself in a duel over Maria-Dolores with Don Alfonso, who is finally stopped by Maria-Dolores's desperate intervention. Tragically, Boomako is shot and killed in the ensuing conflict. As their ship burns and sinks, the trio flees into the open ocean, leaving behind their remaining crew.
The story closes with a mirror of its opening scene—a small boat adrift in the endless ocean, carrying Red and Frog, now with the golden throne in their possession, symbolizing their unending quest for treasure and freedom. This tale is a mixture of adventure, rivalry, romance, and the relentless pursuit of riches on the high seas, showcasing the daring and unpredictable nature of pirates and their escapades.
