Carson, Ryan and the Drew Crew work together to help Nancy.

On the evening of Horseshoe Bay’s annual Harvest Carnival, the body of a mysterious young man is discovered on the Hudson carnival grounds. The Drew Crew is drawn into the case by a host of confounding clues surrounding a new menace terrorizing the town – a killer who has an enigmatic connection to none other than Nancy’s newest foil: Temperance Hudson.

As the gang investigates the Frozen Heart murders, sparks fly between Nancy and her counterpart in law enforcement on Nancy's first day as the community liaison. Temperance makes a startling offer at the police station.

After a major setback in the Frozen Hearts case, Nancy asks Temperance for help with an occult approach to getting answers from a murder suspect. Meanwhile, the Bobbsey entanglement creates a world of trouble for Ace, and George has a long-overdue confrontation with someone from her past.

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.