Words can manipulate minds and mobilize armies. They have the power to unite and to destroy.

No one understands this better than Carter Wainwright, a cultist and enemy from Sam's past and also the person responsible for the death of her partner. Wainwright has resurfaced in Fall River, and his influence is stronger than ever. Attracting fanatics to his sadistic causes has never been a problem for the charismatic leader, but this time, even the most unlikely seem to fall victim to his voice... and Sam is finding it hard to know who she can trust.

After an attack at Brentworth Hospital, a psychiatric care facility where Michael's friends, Tessa and Jimmy, are both residing, Sam begins investigating the hospital and its mysterious new doctor. But her inquiries lead to more questions, no answers, and no connection to Wainwright, and yet Sam cannot let her guard down.

Sam must hunt the most dangerous foe she's ever faced, as well as keep Michael and his friends out of the line of fire. But someone is hunting them at the same time.