When an ancient fissure is jolted in the hills above Los Angeles, a band of long extinct predators, perfectly preserved in suspended animation, awaken. And then the deaths begin, attributed at first to the modern hazards of a rich and teeming metropolis so close to the natural mountain habitat of cougars and wolves. But the ravenous killers are descending from on the mountains, stalking at night, moving from prehistoric relic into a modern nightmare of carnage.

Hannah Hughes, local newspaperwoman, and Jim Grand, a melancholy anthropologist who's happier studying cave paintings than other people, know the threat is real and more dangerous than anyone realizes. Their self-imposed mission is to find the cats and confront living specimens before Sheriff Gearhart destroys what may be the last link to our ancestors' time. And the cats are on a mission too . . .