The Grey Wolf

When Chief Inspector Armand Gamache and his team discover a plot to poison the Quebec water supply they realise that they must act quickly with their investigation but also not tell anyone in order to avoid panic in the community.

The investigation leads to the monastery of Saint-Gilbert-Entre-les-Loups (Saint Gilbert Between the Wolves). During the visit Armand explains to Jean-Guy the story behind the name. An Indian tribe had the story that a Chief felt that he had two rival wolves inside him. The grey wolf wanted him to be strong and compassionate and forgiving while the black wolf wanted him to be vengeful, to be cruel and cunning and to attack first. When asked which wolf would win the Chief replied, "The one that I feed". Armand and Jean-Guy knew that they had to find both 'wolves' quickly to avoid disaster. However they also realise that they do not know who they can trust.

In The Grey Wolf Louise Penny describes the frantic investigations undertaken by Armand, Jean-Guy and Isabelle Lacoste as they strive to discover who is involved in the plot and prevent the deaths of possibly thousands of innocent people.

In this nineteenth book in the Armand Gamache series, the inhabitants of Three Pines do not feature to the extent that they do in the other books but they are there in the background providing support to Armand Gamache and his family. The mystery in The Grey Wolf will be continued in the The Black Wolf to be published in 2025.