Darker Days — Patrick J. O'Brian

After leaving his friends to join his family on a military base, Dan Metzger is thrown into a dangerous situation. Assisting the government, he travels back to Buffalo, New York to search for answers about the zombie apocalypse. Remaining devoted to his brother, a lieutenant commander in the Navy, Metzger begins to question the government's motives. Their soldiers search for answers at great peril, while food and supplies grow scarce.

His friends fare little better when they travel west, only to confront a military threat, followed by a new group that intends to occupy the same town where they hope to settle. Tensions escalate between the two factions, and blood spills when a member of the group goes missing.

While the military puts forth a benevolent front, providing security while taking back more of the country from the undead, Metzger and his friends discover some hard truth. A secret agenda threatens their freedom, and Metzger begins regretting the decision to stay with his family. In a world full of hazards, he can only trust those closest to him.