The Reapers are the Angels (Reapers, #1)

Zombies have infested a fallen America. A young girl named Temple is on the run. Haunted by her past and pursued by a killer, Temple is surrounded by death and danger, hoping to be set free.

For twenty-five years, civilization has survived in meager enclaves, guarded against a plague of the dead. Temple wanders this blighted landscape, keeping to herself - and keeping her demons inside. She can't remember a time before the zombies, but she does remember an old man who took her in and the younger brother she cared for until the tragedy that set her on a personal journey toward redemption. Moving back and forth between the insulated remnants of society and the brutal frontier beyond, Temple must decide where ultimately to make a home and find the salvation she seeks.