While helping his sponge diving friends Marie and Alex Curous off the West coast of Florida near Tarpon Springs, Mike hears bells and is sucked toward a cave. Escaping the current, Mike employs a "diver's parachute" while dropping his weight belt to return to the surface. Learning about the myth of a mermaid, Mike is strangely drawn to investigate the cave again.
Starring Lloyd Bridges as Mike Nelson
Guest Stars: Larry Hagman (Alex Curous), Regina Gleason (Marie Curous), Paul Fierro (Nick Demitrias)
Original airdate: 14 June 1958
Underwater Sequences filmed in Silver Springs Florida