The New York Times bestselling author of The Forgotten Room and Deep Storm is back with a new thriller in which Jeremy Logan follows the trail of a killer unlike any he has ever seen. Jeremy Logan, the renowned "enigmologist," has often found himself in situations where keeping an open mind could mean the difference between life and death, and that has never been more true than now. When Logan travels to an isolated writers' retreat deep in the Adirondacks to finally work on his book, he discovers the remote community has been rocked by the grisly death of a hiker on Desolation Mountain. The attack occured during the full moon and the body has been severely mauled, but the unusual savagery calls into question the initial suspicions of a bear attack. Logan's theories take a dramatic turn when he meets Laura Feverbridge, a respected scientist who is still struggling with the violent loss of her father months earlier. As Feverbridge shares her research with Logan, he begins to wonder whether he is truly up against something he cannot believe exists.