In a small town, the truth can't always set you free...

When a second woman from a group of friends known as "the posse" is murdered in the woods near the New England enclave of Kendalton, FBI agent and profiler Gus Wheeler and his partner are called in to determine if this is a serial killing. He's intrigued by a clue hidden on the body: a memorial picture of a teen who died 25 years ago.

Instead of helping with the investigation, the long-term friends stonewall the agents. But Gus can smell fear beneath their calm masks, fake smiles, and politely vague answers. Digging deeper, he discovers they are being terrorized by cyberstalking, spying, threats and mysterious break-ins. When a third member is hospitalized after a brutal attack, Gus suspects someone in the posse is the hunter instead of the hunted.

Is it the alpha leader Jules, her best friend Maria-married to the chief of police-outsider Mel, or weak link Lizzy? Or someone else bent on revenge? Time's running out, and Gus's life depends on his skill at determining who's the best liar in town.