Nancy, Bess, Agent Park and Temperance have to join forces when an attempt to trap a killer ends up unintentionally unleashing a deadly supernatural entity that feeds on people’s sorrows. Meanwhile, Ace and Ryan discover a haunting at the Historical Society, and George meets a friend from Nick’s past who may have secrets of her own.

Nick, George and Bess unravel the truth behind a college student's mysterious death, while unexpected obstacles prevent Ace from working with Nancy and Agent Park as they grow closer and investigate the hidden origin of the Frozen Hearts Killer.