Thirty million years ago, it was the absolute apex predator of the continent. Tonight, the badlands belong to it again.
When a corporate genetics lab deep in the South Dakota badlands breaches containment during a massive storm, paleontologist Dr. Mara Kessler is thrust into a brutal battle for survival. The resurrected Daeodon—a twelve-hundred-pound prehistoric nightmare known as the "Hell Pig"—is loose, hunting with the crushing power of a grizzly and the shocking problem-solving intelligence of a great ape.
With all communications destroyed, a rising flood blocking the roads, and emergency rescue hours away, Mara joins forces with a rugged local contractor to lead a handful of terrified survivors through a collapsing facility. But as they are systematically stalked through dark corridors and flooded underground utility passages, they realize the terrifying the corporation didn't just bring back a single monster. They engineered a viable population.
To survive the night, Mara must outwit an ancient killer that adapts to their every move and treats human beings as nothing more than prey.