Dr. Steven Sorenson plans to tap the geothermal energy of the Earth's interior by means of a thermonuclear device detonated deep within the Earth. This experiment causes a crack to form and grow within the Earth's crust, which threatens to split the earth in two if it is not stopped in time.
Dana Andrews
as Dr. Stephen Sorenson
Janette Scott
as Dr. Maggie Sorenson
Kieron Moore
as Dr. Ted Rampion
Alexander Knox
as Sir Charles Eggerston
Peter Damon
as John Masefield
Sydna Scott
as Angela
Gary Lasdun
as Markov
John Karlsen
as Dr. Reynolds
Alfred Brown
as Dr. Bill Evans
Mike Steen
as Steele
Todd Martin
as Simpson
Jim Gillen
as Rand
