Each hour-long episode of this chilling psychological drama tells the harrowing, firsthand stories of living with a person who became a killer. Viewers will be put in the shoes of the loved one, who lived through this incredible experience —from first noticing that something is amiss, to interpreting all of the puzzling signs and clues, to eventually coming face-to-face with the horrible truth: that the person they loved, the person they trusted, has a very dark side.