A horrific crime that defies explanation, a rookie FBI agent in uncharted territory, and an extraordinary hero for the ages: an investigation spirals out of control in this heart-pounding thriller.

Odessa Hardwicke's life is derailed when she's forced to turn her gun on her partner, Walt Leppo, a decorated FBI agent who turns suddenly, inexplicably violent while apprehending a rampaging murderer. The shooting, justified by self-defense, shakes the young FBI agent to her core. Devastated, Odessa is placed on desk leave pending a full investigation. But what most troubles Odessa isn't the tragedy itself — it's the shadowy presence she thought she saw fleeing the deceased agent's body after his death.

Questioning her future with the FBI and her sanity, Hardwicke accepts a low-level assignment to clear out the belongings of a retired agent in the New York office. What she finds there will put her on the trail of a mysterious figure named John...