The 20th mystery in the #1 New York Times-bestselling Armand Gamache series.

Somewhere out there, in the darkness, a black wolf is feeding.

Several weeks ago, Chief Inspector Armand Gamache of the Sûreté du Québec and his team uncovered and stopped a domestic terrorist attack in Montréal, arresting the person behind it. A man they called the Black Wolf.

But their relief is short-lived. In a sickening turn of events, Gamache has realized that plot, as horrific as it was, was just the beginning. Perhaps even a deliberate misdirection. One he fell into. Something deeper and darker, more damaging, is planned. Did he in fact arrest the Black Wolf, or are they still out there? Armand is appalled to think his mistake has allowed their conspiracy to grow, to gather supporters. To spread lies, manufacture enemies, and feed hatred and division.

Still recovering from wounds received in stopping the first attack, Armand is confined to the village of Three Pines, leading a covert investigation from there. He must be careful not to let the Black Wolf know he has recognized his mistake. In a quiet church basement, he and his senior agents Beauvoir and Lacoste, pore over what little evidence they have. Two notebooks. A few mysterious numbers on a tattered map of Québec. And a phrase repeated by the person they had called the Grey Wolf. A warning...

In a dry and parched land where there is no water.

Gamache and his small team of supporters realize that for the Black Wolf to have gotten this far, they must have powerful allies, in law enforcement, in industry, in organized crime, in the halls of government.

From the apparent peace of his little village, Gamache finds himself playing a lethal game of cat and mouse with an invisible foe who is gathering forces and preparing to strike.