When Faith Lorrell came across the stopped train in the middle of the San Zechariah Valley, she assumed it was there for maintenance purposes. Then she discovered the wrecked boxcar and the mutilated corpse, and realized something terrible had happened. Next thing she knew, she was running for her life. As the evening rages on, the body count rapidly climbs while prehistoric creatures, freed from their transport, set out to wreak havoc in the valley. The tension mounts when the head of the organization and his band of cutthroats attempt to recapture the animals and hide the evidence of the bloodshed.

With the situation escalating, Faith finds herself in an alliance with a reluctant company employee and a docile triceratops. Together, they set out to expose the company's actions and bring an end to the mayhem. It proves easier said than done, as they fight to survive the killing spree of a ravenous modern-day raptor. The reptilian proves to only be the tip of the iceberg, for the heroes soon come face-to-face with the gargantuan apex predator: the Tyrannosaurus Rex.

Over fifty feet in length, it has the strength to wreck buildings, flatten vehicles, and pulverize flesh. Armed with crushing jaws, powerful hind legs, and a bad temper, it kills even when it isn't hungry. It knows no compassion, for it is a cruel TYRANT.