Former Ranger Jack Smith watched an Army bio-warfare experiment go horribly wrong in an Afghan village in 2001, escaping only after he turned to a makeshift mace and bayonet to destroy the skulls of the infected creatures that bullets to the chest could not stop. With the traumatic experience seared into his mind, he earned his Ph.D. in ancient history and began developing medieval weapons-making skills after he left the service. When the virus broke free from the Hindu-Kush Mountains a decade later and rapidly spread across the globe, Jack knew how to fight the monsters created by the infection: 21st century technology combined with deadly medieval tactics and weaponry. Jack and his former squad-mates lead a resistance against a zombie apocalypse in a crusade to ensure humanity's survival.