She likes the sudden seconds of sheer terror. The neon dreams fit perfectly with the dreams that wake her up at night: about the man she loved and lost, about the constant temptations in her life, and about the odds that inevitably she’ll be in the right place at the right time to look naked, human madness in the eye.

Welcome to the world of Susan Pulaski, an unconventional and unusually subversive Las Vegas police behaviorist who’s already been canned once and has never been needed more. In the Sin City, someone is ritually murdering handpicked victims, each with dirty secrets in their past. The killer’s gimmick: Not only does he leave behind parts of the victims’ bodies, he also writes obscure mathematical formulas–in their blood. Pulaski doesn’t have a clue what the codes mean. But she knows someone who will.

Darcy O’Bannon is a twenty-six-year-old whose autistic savant skills are perfect for unraveling such mysteries as how many rivets are in the Eiffel Tower and how many Elvis impersonators there will be in the year 2020. As it turns out, innocent Darcy can also think along the arcane lines of Vegas’s most savage serial killer, peering into a numerological mystery that stretches back hundreds of years.

With her own life one spark away from going off the rails, her department turned against her, and the lives of those she cares most about in jeopardy, Pulaski hunts for dangerous prey in the shadow of the Strip–with herself as the perfect bait. And the closer she gets, the more terrifying and intriguing the case becomes, for the person she’s tracking possesses truly ingenious powers–and a heart full of hate.

The incomparable William Bernhardt brings to life America’s most fascinating city and the people who police it, while he invites the reader to join one woman’s fight to stay sane, stay alive, and keep a killer from making the most shocking score of all.