Navy Commander Alan Roberts is assigned to lead an expedition to Little America in Antarctica to investigate reports of a mysterious warm water inland lake discovered a decade earlier. His helicopter and its small party, including reporter Maggie Hathaway, is forced down into a volcanic crater by a fierce storm. They find themselves trapped in a lush tropical environment that has survived from prehistoric times.
Jock Mahoney
as Commander Harold 'Alan' Roberts
Shirley Patterson
as Margaret 'Maggie' Hathaway
William Reynolds
as Lt. Jack Carmen
Henry Brandon
as Dr. Carl Hunter
Douglas Kennedy
as Capt. Burnham
Phil Harvey
as Machinist's Mate Steve Miller
Kenner G. Kemp
as Officer at Briefing / Officer on Ship (uncredited)
Bing Russell
as Radio Operator (uncredited)
Bert Stevens
as Officer at Briefing (uncredited)
Tom Coleman
as Man at Briefing (uncredited)
