Imagine a world three years after a nuclear attack hits downtown Pittsburgh. No power. No radio. No communication. You emerge to find bloodthirsty creatures roaming the streets. The world as you knew it...gone.

The world wasn't supposed to end like this....

Fear what comes with the darkness.

The desolate streets of downtown Pittsburgh in 2073 are a constant reminder of the missile attack that forever changed the lives of the surviving scientists and students hidden in the fallout shelter of Helmsby's Genetic Research Center. Believing themselves to be the only survivors, they station themselves inside the center until food supplies near depletion. Thinking the fallout has lessened, they emerge three years later to discover strange creatures patrolling the streets in search of human flesh and blood. The creatures possess the ability to shift their genomes and alter their appearances by realigning their genetic sequences.

Daniel Hutchinson, their leader, teams with Lucas Ridale, and together they set out to scavenge the area for food and supplies with the hope to find other survivors. But Daniel's most recent journey uncovers mysteries more frightening than the shifters. He discovers the tip of Pittsburgh has been fenced off from the rest of the area. Low-flying helicopters observe the streets, making him ponder the question: Were the shifters released as simply part of a military experiment with humans being their prey?