When a melting iceberg releases a prehistoric giant praying mantis, a palaeontologist works alongside the military to kill it after it attacks scientific outposts on its way to Washington and New York.

Craig Stevens
as Col. Joe Parkman

William Hopper
as Dr. Nedrick 'Ned' Jackson

Alix Talton
as Marge Blaine

Donald Randolph
as Gen. Mark Ford

Florenz Ames
as Prof. Anton Gunther

Paul Smith
as Corporal

Paul Campbell
as Lt. Fred Pizar

Pat Conway
as Sgt. Pete Allen

Phil Harvey
as Lou

Helen Jay
as Mrs. Farley