Investigative apprentice Lyra Brazier, the newest resident of Burning Cove, is unsettled when her boss suddenly disappears. Lyra knows something has happened to Raina Kirk, and tracks down her last known appearance at an exclusive hotel and health spa. The health spa is known for its luxurious offerings and prestigious clientele, and the wealthy, socialite background Lyra desperately wanted to leave behind is perfect for this undercover job. What Lyra lacks in investigative experience she makes up for in gut instinct, and her gut isn't happy that she's saddled with a partner by Luther Pell, Raina's dangerous lover, who wants to bring in someone with more experience to help.

Instead of the suave, pistol-packing private eye she expected, though, Simon Cage is a mild-mannered antiquarian book dealer with a quiet, academic air, and a cool, remote gaze. Lyra suspects that Simon is much more than what he seems, and her instincts are confirmed when they arrive at the spa and pose as a couple: Simon has a unique gift that allows him to detect secrets, a skill that is crucial in finding Raina.

The unlikely duo falls down a rabbit hole of twisted rumors and missing socialites, discovering that the health spa is a façade for something far darker than they imagined. With a murderer in their midst, Raina isn't the only one in grave danger--Lyra is next.