Andrew Klavan 
Animal Hour 

Voices invade a young woman’s head, compelling her to kill When Nancy Kincaid comes into work, an unfamiliar woman tells her to leave. This is Nancy Kincaid’s office, the woman says, but you are not Nancy Kincaid. As Nancy protests, her memory grows fuzzy and her reason seems to slip away. None of her workmates recognize her, and she is distracted by a voice in her head that suggests she shoot them all. Ejected from her office, she collects herself in the park. A homeless man pesters her, mumbling that at eight o’clock—the animal hour—there is someone she has to kill. Over and over she tells him to leave, until she finds the pistol in her purse. She kills the bum and sets off a whirlwind of insane violence that will not stop until the animal hour comes to pass.