When the cable breaks on their diving bell four people find themselves trapped in a hidden underwater world.
John Carradine
as Prof. Millard Wyman
Robert Clarke
as Craig Randall
Phyllis Coates
as Dale Marshall
Allen Windsor
as Paul Whitmore
Sheila Noonan
as Lauri Talbott
George Skaff
as Dr. J.R. Matheny
Maurice Bernard
as Old Man in the Caverns
Joe Maierhouser
as Jim Wyman
Lloyd Nelson
as Wilson, Sonar Man
Harry Raven
as The Captain
Milt Collion
as Hank
Lowell Hopkins
as Reporter
