While trying to uncover the truth about a long-buried history between Lucy Sable and Ryan Hudson, Nancy finds herself in the curious position of having to strike a deal with Horseshoe Bay’s newest and most suspect widower.

Nancy and the Drew Crew follow the latest Lucy Sable murder lead, while simultaneously working to uncover the attempted murder of someone in their community. When both investigations lead back to the same person, Nancy and Nick confront the suspect with their findings.

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.

Nancy launches a new investigation to find a group of missing bodies from Horseshoe Bay's cemetery that have been dug up and stolen – or have possibly risen. As Nancy is drawn into this ghostly case, a string of unexplained paranormal crimes leads the Drew Crew to believe that the literal sins of the town's past have returned to haunt the living. Meanwhile, Nancy struggles with yearning for Ace, the man she loves. But when a slow-burning attraction begins between Nancy and the son of Ryan Hudson's newest enemy, Nancy must decide whether this love interest is worth the ire of both her father and Ace – whose own heart may be tempted by a new relationship too.

Nancy and the Drew Crew’s mission to save Horseshoe Bay from sins of its past comes to an epic conclusion as they must contend with Nancy’s most shocking discovery yet, one that will determine the fate of her star-crossed love with Ace.