Synesthesia, a neurological condition that, among other sensory-heightening effects, allows you to see music and smell colors, helps a bar owner find the identity of a threatening letter writer.
Mackenzie "Mack" Dalton, the owner of Mack’s Bar, has a history of solving mysteries. Now, however, she’s embroiled in a mystery of her own stemming from a series of threatening letters that promise death to those closest to her if she doesn’t follow the clues provided by the letter writer. As she tries to solve the mysteries posed by the letters, Mack also ponders the bigger mystery of who’s writing them. Though she’s been instructed not to seek the help of the police, including her boyfriend, Detective Duncan Albright, the threat has merely sent her collaboration behind closed doors. While she’s still seeing Duncan, she’s found the perfect cover in Malachi O’Reilly, an undercover cop solving a case of his own whose details are withheld from readers. Mal and Duncan aren’t Mack’s only resources: she’s also been using the bar as a gathering place for the Capone Club, a group of friends who are equally devoted to a good mystery. If she’s lucky, the club will help Mack solve the letter writer’s clues, buying her time to figure out her mysterious correspondent’s motives and identity. As she investigates alongside Mal, with whom she shares a growing mutual attraction, Mack begins to suspect that the Capone Club may not help her as much as she’d hoped because the letter writer may actually be a club member. Luckily, Mack’s synesthesia, a neurological quirk she’s turned into an asset, may give her an edge that guides her to the writer’s identity before anyone gets hurt.
Though Abbott resolves the mystery posed by Shots in the Dark (2016), which first introduced the threatening letters, there’s hardly enough plot here for a stand-alone volume.