When a massive explosion at a top-secret prison known as the Pit allows notorious serial killer Richard Harris to escape, disgraced FBI agent Bex Henderson is called back into action to hunt him down before he kills again.

Dr. Ezekiel Malak, a hospital psychiatrist turned serial killer, is prowling for new victims in Chicago. 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.

When Bex and the team race to stop Roy Barber, known as the Couples Killer, before he strikes again, they uncover a chilling scheme that puts Roy's crimes in an entirely new light.