Classic high-seas adventure set in the 1600s. The story follows a British sea captain who must go undercover, join a pirate band, and capture the notorious Captain Henry Morgan (Robert Stephens). However, Morgan is on to the ruse and is well prepared when the sea captain makes his move. As the two engage in mortal combat, they are knocked unconscious and dragged to the governor of Tortuga who prepares to hang them both as pirates. Fortunately, a stowaway aboard the pirate vessel steps forward and reveals their true identities.