Callahan Rook is a solitary engineer commanding a massive, two-mile-long automated freight train across the desolate, dead-zone stretch of the Mojave Desert. His isolated night shift shatters when the train's diagnostic panel registers an impossible anomaly: the rear cars are rapidly gaining thousands of pounds of weight.
Expecting to find train hoppers on the exterior security cameras, Callahan instead witnesses a biological nightmare. The heavy steel doors of the shipping containers are violently peeled open from the inside. The cargo isn't industrial scrap-it is a horde of grotesque, imperfectly cloned copies of Callahan himself, and they are systematically climbing across the roof toward the engine.
When the entities cut the pneumatic brake lines, Callahan is forced to abandon the safety of the armored cabin. Fighting deafening winds on top of a train moving at seventy miles per hour, he must manually decouple the compromised cars. But the corporate shipping manifest was a cover for an illicit biometric disposal run, and his desperate, mutated doppelg ngers want to steal his life. With no weapons and no way to call for help, Callahan must reroute the speeding behemoth toward a condemned canyon drop and fight his way through his own genetic horrors to survive.