The Dark Door (Constance and Charlie Series #2)

Something is causing an outbreak of madness and death in the vicinity of abandoned hotels around the country, and someone is torching abandoned hotels. Charlie and Constance are hired to find and stop the arsonist, but as they are drawn deeper and deeper into the mystery they become aware that government agencies are also probing, not for the arsonist, but for the source of whatever it is that brings about murderous madness, that causes bodies to rise and walk, and makes people vanish. What kind…