In the West Indies in the 17th century a man goes under cover a ships surgeon on Blackbeard's ship to try and prove that Henry Morgan who is now a government official in Jamaica is still actually involved in piracy. On board the ship is a beautiful woman whose intentions are far from clear. This is a typical RKO Technicolour swashbuckling film that is not a great film, but the highlight of the film is Robert Newton's portrayal of Blackbeard the pirate. His portrayal of a pirate has become the benchmark that others have followed. His performance dominates the film and over shadows the other performances even the elegance of Linda Darnell.