Inside the department, they're called Tin Collectors: Internal Affairs Agents, the police of the police. If they catch you breaking the rules, they'll come after your badge. If they want you badly enough, they'll collect more than just your tin.

LAPD Detective Shane Scully is startled awake in the middle of the night by a call from his ex-partner's wife, who is being beaten by her abusive husband. After racing to their house to stop the fight, Scully ends up killing his ex-partner, a cop who is beloved within the department. Suddenly, Scully finds himself an outcast, shunned by his fellow cops, who intend to exact vengeance no matter what the cost. Internal Affairs zeroes in on the "renegade" cop with their sharpest young prosecutor, the ice queen Alexa Hamilton, who has her own reasons for taking revenge on Scully.

Desperate to save his career, Scully starts kicking over rocks within the LAPD. What he uncovers is pure evil: a conspiracy going to the very top that ultimately threatens not just his own life but that of a young teenage boy, Chooch, entrusted to Scully's care by his mother, Sandy Sandoval. Known as the Black Widow, Sandy is a beautiful and courageous woman who also happens to be LAPD's most important undercover informant, and Scully will do anything to keep her son safe.

Stephen J. Cannell combines mystery, violence, loyalty, and passion in a tale with an ending as unpredictable as L.A. itself.