Calisto Casey is a Detective in a small Police Department in Windsor Locks, Connecticut. She's the epitome of a good Detective, she's intuitive, mentally strong and clever. She also has a dark past that helps her find her prey in ways that others don't understand. She puts her unusual skills to good use, while wishing that they didn't come with such a price. She's good at catching deviants. She hates how she came upon these exceptional skills, but she uses them to help cleanse her little corner of the world.
Calisto is not alone in her desire to cleanse the world, but the man that she is hunting is most certainly not on the same page as she is, not even close. He sees Demons in the form of innocent women that he finds attractive. But, he is a religious man as well, and as such he believes that he has the power to exercise those horrible Demons. He believes that he is successful in every attempt at exorcism, it's not his fault that the women can't handle the strain and die while he is trying to help them. Consequently, he is leaving a string of murders in Windsor Locks that's making the city fathers nervous.
To catch her killer Cali needs to know where he's hunting, to find that, she needs to connect the victims but she can't do that without their names. She has theories, and she has small scraps of evidence, but how is she going to find her killer before he kills again if she can't make the connections? Her killer is moving faster with each death. She needs help, but when it walks through the door, will she accept it?