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. This Irwin Allen mini-disaster film made in 1979 was shelved for a number of TV seasons, as was his "The Night the Bridge Fell Down", made back-to-back with this one by the same director and much of the same crew.