Dr. Ezekiel Malak, a hospital psychiatrist turned deranged killer, is prowling for new victims in Chicago, so Bex and the team work to find a method to his madness in a desperate bid to get ahead of him — until Malak makes a move no one saw coming.

Arlo Brandt, a hoarder-turned-serial killer, emerges from the Pit with newly found purpose; as Arlo hunts for innocent victims, Bex and the team must get inside a deranged mind.