Army radiation experiments awaken a subterranean monster from a fissure that feeds on energy and proceeds to terrorise a remote Scottish village. An American research scientist at a nearby nuclear plant joins with a British investigator to discover why the victims were radioactively burned and why, shortly thereafter, a series of radiation-related incidents are occurring in an ever-growing straight line away from the fissure.
Dean Jagger
as Dr. Adam Royston
Leo McKern
as Inspector McGill
William Lucas
as Peter Elliott
Edward Chapman
as John Elliott
John Harvey
as Maj. Cartwright
Michael Ripper
as Sgt. Harry Grimsdyke
Anthony Newley
as LCpl. 'Spider' Webb
Ian MacNaughton
as Pvt. Haggis
Peter Hammond
as Lt. Bannerman
Kenneth Cope
as Pvt. Lansing
Michael Brooke
as Willie Harding
Frazer Hines
as Ian Osborn
