In the Pacific Ocean, 100 miles from Guadalcanal, a U.S. destroyer discovers a sunken submarine when the destroyer's sonar picks up the sound of tapping on metal. The crew sends below a diver, who confirms that it's a sunken U.S. submarine. A bit of research reveals that it went down 20 years earlier, during World War II. Meanwhile, the chief boatswain's mate Bell has been acting strangely, and the ship's doctor believes Bell is having a mental breakdown. Not coincidentally, the submarine they've discovered is the one from which Bell was the only survivor -- and believing himself responsible for the ship's sinking, he comes to fear that his former crew mates are calling him to join them.
—garykmcd