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.

Reunited with his brother David, former Army Ranger Jack Smith begins to fortify a network of survivors in a world plagued by a viral epidemic that turns humans into flesh eating monsters. Over time, the once slow, zombie-like creatures become stronger, faster, and, apparently, smarter. A young man named Luke, who travelled with David's group on the journey from Cleveland to Indiana, seems to have a sixth sense about these "hunters," and this ability makes him an especially valuable ally in humanity's war against the infected. While medieval weaponry and modern armor remain the most effective defense when facing the creatures in combat, Jack and his allies learn that there are even deadlier enemies lurking beyond the battlefield.

Former US Army Ranger Jack Smith successfully defended his compound in Northern Indiana during the first stage of the outbreak. His brother, David, failed to heed Jack's warnings and ended up trapped in Cleveland in the middle of an apparent zombie apocalypse. In this second book of the Zombie Crusade, David Smith attempts to lead a small but deadly band of survivors to his brother's fortress in Indiana. They risk their lives every day travelling the rivers of the Midwest, and they become a close-knit community of well-armed survivors who discover that the zombies are evolving into fast-moving hunters.