A party of tourists -- including a state senator, a park ranger who was her one-time lover, a cantankerous professor, and an escaped convict -- are trapped deep inside the caverns of an unnamed national park, rescued briefly, and then caught in a second cave-in.
as Ranger Gene Pearson
as Senator Kate Lassiter
as Joe Johnson
as Prof. Harrison Soames
as Liz Johnson
as Ann Soames
as Walt Charles
as Tom Arlen
as Doctor at Prison
as Larry Munson
as Herb
as Cooper
as Jack Miller
as Ray