On the morning of her first day as the new captain of the Twentieth Precinct, Nikki Heat is rocked when her NYPD shrink washes up dead on the banks of the Hudson River. But the jarring murder of the man who knew her most intimate secrets is only the first of a series of blows to batter New York City's top homicide detective. She is soon blindsided by the discovery that her fiance, Pulitzer Prize-winning reporter Jameson Rook, had been secretly meeting her psychologist as part of an explosive investigative article he is writing for a magazine.Nikki's sense of betrayal deepens when Rook refuses on ethical grounds to share confidential information he has learned about the victim. His headstrong stance and continued meddling in Heat's case strain their engagement to the breaking point as their professional lives drive straight for a collision.In this riveting new novel from his blockbuster series, New York Times bestselling mystery author Richard Castle steers Nikki Heat full throttle through the heart-pounding obstacle course of her most daunting and dangerous case yet. Her stakes have never been higher or more emotional as she races to stop an ingenious repeat killer with a chilling MO and a long list of targets. In her quest for justice, Heat confronts a narcissistic dot-com tycoon, deals with a headline-hungry auto-safety whistle-blower, weathers a hacking attack that cripples all of New York City's police technology, and faces unrelenting danger to herself and the man she may yet marry-if they both survive this deadly ride.