A man-made apocalypse threatens mankind. Three strangers navigate the chaos: an expectant mother, a teenage girl, and an armed loner. One hundred years later, their survival leads to a battle to vanquish the Twelve, a dozen humans transformed by an ancient virus into a terrifying threat that will bring what is left of the human race to what survivors think will be the brink of annihilation. But the enemy has evolved with a new plan more horrifying than man's extinction. To bring the Twelve down, one of humanity's heroes will have to pay the ultimate price.