A pretty psychiatrist is saved from an accident by a man who, after hitting his head on a rock, believes he is Santa Claus. As she nurses him back to health at her institute, he brings the spirit of Christmas to the hospital.

Under the border leading into Mexico, within a labyrinth of caves, a deadly presence haunts all who enter. For four friends on an expedition, the caverns become an underground graveyard as the tortured ghosts prey upon them, one by one.

Two young couples head into the New Guinea wilderness in an effort to find Michael Rockefeller, the heir to the Rockefeller fortune who disappeared in 1961.