Tom Merriam, a young officer joins the crew of a ship, the Altair. At first all seems well and Merriam bonds with the Captain, Will Stone. However, as the cruise continues, several crewmen die mysteriously. Merriam comes to believe that Captain Stone, who is obsessed with authority, is responsible. When they dock at the first port, Merriam attempts to expose the Captain's madness but is discredited and subsequently dismissed.
Soon after this, Merriam is involved in a fight and knocked unconscious. One of his former shipmates (unaware that he was dismissed from the ship) finds him and returns the unconscious man to the Altair before she steams from port. Merriam wakes up on the ship and fears that the insane Captain Stone may now attempt to kill him for vengeance.