Lt. Commander Mason Cole never intended to follow his brother into law enforcement, but the murder of a loved one gave him the motivation needed to take a position as the head of Chicago s Serial Crimes Unit. Along with his brother, Detective Devon Cole, former FBI Profiler and Technical Analyst Melinda Kade and Detective Piper Torello, Mason is tasked with finding some of the cities most prolific serial killers. As a former Navy SEAL, Mason has seen some of the worst the world has to offer, but nothing could have prepared him for his initiation into the world of a serial killer.