Billy Harney was born to be a cop. The son of Chicago's chief of detectives, whose twin sister is also on the force, Billy plays it by the book. Alongside Detective Kate Fenton, Billy's tempestuous, adrenaline-junkie partner, there's nothing he wouldn't sacrifice for his job. Enter Amy Lentini, a hard-charging assistant state's attorney hell-bent on making a name for herself-who suspects Billy isn't the cop he claims to be. They're about to be linked by more than their careers.A horrifying murder leads investigators to an unexpected address-an exclusive brothel that caters to Chicago's most powerful citizens. There's plenty of incriminating evidence on the scene-but what matters most is what's missing: the madam's black book. Now shock waves are rippling through the city's elite, and everyone's desperate to find it.As everyone who's anyone in Chicago scrambles to get their hands on the elusive black book, no one's motives can be trusted.