In a world where God is a drug, one woman has to get sober. Lyda Rose was one of the neuroscientists who helped create Numinous, which produces the illusion of a personal deity, but since unwittingly overdosing, she has been haunted by her own visions of an angel she calls Dr. Gloria. After a stay in an asylum, she thinks she's put it behind her. Then others start overdosing. Who is still producing the drug, and why?