Harry, Doug (Frank Langella), and Modi, three brothers active in the Caribbean, each keep one-third of a treasure map. Doug wants to monopolize the treasure and seriously injures Harry to death. Harry's daughter Morgan (Geena Davis) takes over the Morning Star pirate ship and inherits her father's wish of revenge and treasure hunting. Morgan takes off the treasure map on her father's scalp, but because she can't recognize the Latin on the map, she lands on the ship for help. It happens that habitual thief Shaw (Matthew Modine) is sold as a slave by the government. Morgan relies on Shaw's translation ability to buy him, and soon shows her brave nature in the pursuit of the government army. Morgan and others go to Modi, but Doug appears unexpectedly. Modi dies in the chaos, and Shaw takes the second treasure map for himself. Morgan punished Shaw for his disloyalty, but was unable to get rid of Doug who was following him. Eventually the crew mutinied and Morgan lost the Morning Star. Although Shaw assisted Morgan in discovering the location of the treasure on Cutthroat Island, how easy would it be to obtain the treasure under the siege of Doug and the government troops?