A knock on Spenser's office door can mean only one thing: a new case. This time the visitor is a local lawyer with an interesting story. Elizabeth Shaw specializes in wills and trusts at the Boston law firm of Shaw & Cartwright, and over the years she's developed a friendship with wives of very wealthy men. These rich wives have a shared secret: they've all had an affair with a man named Gary Eisenhower—and now he's blackmailing them for money. Shaw hires Spenser to make Eisenhower "cease and desist," so to speak, but when women start turning up dead, Spenser's case goes from blackmail to murder.

As matters become more complicated, Spenser's longtime love, Susan, begins offering input on the case, analyzing Gary's behavior patterns in hopes of opening a new avenue of investigation. It turns out that not all of Gary's women are rich. So if he's not using them for blackmail, then what is his purpose? Spenser switches tactics to focus on the husbands, only to find that innocence and guilt may be two sides of the same coin.