It begins, as terror so often does, with a disappearance -- two men lost in the foothills of the Santa Ynez Mountains, a pair of back packs the only evidence that they'd been near the mysterious sinkhole. An ancient fissure has been jolted open in the hills; the sprawling teeming metropolis of Los Angeles carries on, oblivious to the constant geological changes in the earth beneath it.

Something is descending, stalking at night, moving ever closer to civilization. The official response to death is more destruction: Sheriff Malcolm Gearhart wants to destroy the creatures before anyone is even sure what they are, to annihilate any beast that would dare to attack man. But anthropologist Jim Grand and local newspaperwoman Hannah Hughes see another way -- a dangerous path, but one that might save the last link to a prehistoric time.

And as the humans battle to steer the right course, the cats are getting closer...