Henry Cimoli and Spenser have been friends for years, yet the old boxing trainer has never asked the private eye for a favor. Until now. A heavy-handed developer is trying to buy up Henry's condo on Revere Beach and sends thugs to move the process along. Soon Spenser and his apprentice, Zebulon Sixkill, find a trail leading to a mysterious and beautiful woman, a megalomaniacal Las Vegas kingpin, and plans to turn to a chunk of land north of Boston...

Ten years ago, Spenser helped a teenage girl named Mattie Sullivan find her mother's killer. Now Mattie is a college student with a side job working for the tough but tender private eye. In her first big case, Mattie links the exploitation of dozens of girls to an eccentric billionaire and his sadistic henchwoman. Spenser and trusted ally Hawk must again watch out for Mattie as she unravels a massive sex-trafficking ring that will take them from Boston...