Written by Rod Serling, this 60-minute Twilight Zone episode gets under way when a U.S. Navy destroyer begins picking up unusual sounds on its sonar. Investigating, a frogman finds the remains of a sunken submarine -- and hears the sound of clanking from within. This information has a profound effect on the destroyer's chief petty officer Bell (Mike Kellin), and Captain Beecham (Simon Oakland) wants to find out why. Future TV leading man Bill Bixby appears in a supporting role. "The Thirty-Fathom Grave" was first telecast January 10, 1963. ~ Hal Erickson, Rovi