It is a story book. Tom Merriam (Russell Wade), a young merchant marine officer, joins the crew of the ship Altair. At first, all seems well and Merriam bonds with the captain, Will Stone (Richard Dix). The ship, already shorthanded due to the death of a crew member before it left port, loses another ('the Greek') when he develops appendicitis. (Taking direction over the ship's radio, the captain is to perform the appendectomy, but he is unable to make the incision. Instead, Merriam successfully remove's the sailor's appendix, but – feeling he should be loyal to the captain and spare him embarrassment – swears the radio operator to secrecy. Afterward, the captain has a self-serving explanation for his failure. ) One of the crew, Louie (an uncredited Lawrence Tierney), tells the captain he should pull in to port and take on new crew. The captain says 'You know, there are captains who might hold this against you, Louie'. Shortly after, the captain closes the hatch to the chain locker with Louie inside, and Louie is crushed to death by the chain. Merriam believes that Captain Stone, who is obsessed with authority, did it intentionally. When they dock at the fictional Caribbean island of 'San Sebastian' (which had appeared in RKO's I Walked with a Zombie—another Lewton production—and later in RKO's Zombies on Broadway), Merriam attempts to expose the Captain's madness at a board of inquiry. The crew all speak favorably of the captain, including the Greek, who credits the captain with saving his life. Merriam states his intention to leave the Altair.