Meredith finds herself trapped in a labyrinth of caves below the Carlsbad Caverns when she is propelled downward during an earthquake while visiting with some friends. She is separated from those with her in the Great Room, and lands on a small ledge in complete darkness. To her relief she finds there is someone else with her, a mysterious male who manages to extricate her from her perilous position to a chamber below. Together, they must find a way out or perish.