The Grey Wolf

Published in 2024, The Grey Wolf by Louise Penny is the 19th installment of the Chief Inspector Gamache series of mysteries, set in Canada. The book was a #1 New York Times Best Seller and was named a Best Book of 2024 by Amazon. The series has won various awards, including the CWA Dagger and the Agatha Award (seven times) and was adapted into an Amazon series called Three Pines. The Grey Wolf explores themes relating to water control, religious and secular thought, and the effects of events on faith in oneself or in religion.

This guide refers to the Minotaur Books hardback edition.

Content Warning: The source material and guide feature depictions of death, graphic violence, addiction, substance use, death by suicide, and cursing.

Plot Summary

Detective Armand Gamache ignores repeated phone calls and eventually tells the caller to stop. His wife, Reine-Marie, understands this uncharacteristic aggression when she sees that the caller was Jeanne Caron, Armand’s nemesis, who harmed his son. While Armand and Reine-Marie meet friends in a bistro in Three Pines, they learn that their apartment in Montreal has been broken into. Jean-Guy Beauvoir, Armand’s son-in-law and second-in-command, checks out the apartment. The only thing missing is Armand’s raincoat. It’s delivered to the Sûreté (police) and has two notes for Armand in the pockets. One is a request for a meeting, and the other is a recipe containing herbs that has the word “water” written on the back.

Armand attends the meeting, along with Isabelle Lacoste (his other second-in-command) and other Sûreté agents. A man named Charles Langois introduces himself to Armand and gives vague information about the importance of water and the Sûreté being compromised. As Charles exits the cafe, an SUV hits and kills him. His last word to Armand is “family.” Armand searches Charles’s apartment, where he finds a missing map and learns that Charles worked for Action Quebec Bleu (AQB) as a marine biologist, investigating pollution in lakes. Jean-Guy interviews AQB’s director, while Armand talks to Charles’s parents, who lie, saying that they haven’t seen him recently.

At the Sûreté station, Armand works on a case of two murders that look like mob hits, though the detective who works organized crime cases, Tardiff, doesn’t think the hits connect to the Mafia. Armand’s boss, Toussaint, asks him to attend a news conference, where a vlogger named Shona (who holds a misguided grudge against Armand) attacks him. Afterward, he investigates The Mission, where Charles once stayed and later worked as a volunteer. There, Armand finds videos of Charles with Jeanne.

Since the clues point to potential contamination or poisoning of the water supply, Armand invites his children’s families to stay in Three Pines, where a local spring provides well water. He discovers that a monk he knew from a previous case, Dom Philippe, stayed at the local bed and breakfast, which is owned by Armand’s friends. Philippe left a bottle of chartreuse and a recipe for a drink at the bed and breakfast. In the local church, Philippe left a note for Armand: the other half of the recipe and a quote from T. S. Eliot. Armand shares his concerns about the water supply with the assistant commissioner of the Royal Canadian Mounted Police (RCMP), David Lavigne, who later turns out to be corrupt.

Armand and Jean-Guy travel to Dom Philippe’s monastery, Saint Gilbert Between the Wolves. They discover that Philippe is gone and that Simon is the acting abbot. In the monastery, Jean-Guy finds Charles’s hidden map, which has cryptic notes about companies polluting lakes. Armand walks around the lake near the monastery, sees a wolf, and tells Jean-Guy about the two wolves in the monastery’s name: gray (good) and black (evil). Simon says that both Philippe and Frere Sebastien received letters from the Vatican and left. Armand orders Isabelle to follow up in Rome and Jean-Guy to go to Washington, DC, where Sebastien taught at seminary.

Jean-Guy learns that Sebastien, Brother Robert, and Sister Irene got in trouble for singing in karaoke bars while wearing their robes. Next, Jean-Guy meets with Armand’s friend in Washington, General Whitehead, to discuss the effects of an attack on the water-treatment plant. Meanwhile, Armand learns that botulinum is the most likely agent to poison a water-treatment plant and that it’s often transported in an aspirin bottle. Through Archbishop Fleury and other clergy, he learns that Dom Philippe’s birth name is Yves and that he is from Blanc-Sablon. In Rome, Isabelle finds Irene. In Three Pines, Armand finds the bottle of chartreuse that Yves left at the bed and breakfast and discovers that it came from the one monastery in France that makes it. Armand sends Isabelle there with Irene and his friend from the Paris police, Claude.

Armand meets with his vlogger nemesis, Shona, asking her to look into the pollution and poisoning of water. He discovers the identity of the SUV driver, Parisi, and has Jean-Guy look for him. At The Mission, Jean-Guy discovers that the SUV driver was friendly with Yves. Meanwhile, Armand visits Yves’s family in Blanc-Sablon and learns that Jeanne is Yves’s niece. He goes to Jeanne’s office, but she isn’t there. Instead, Armand takes her assistant and an RCMP agent whom David sent with him to Three Pines. They find Jeanne and Yves together in the church there.

The RCMP agent shoots and kills Yves and hurts Jeanne, but she escapes. Armand holds Yves’s hand as he dies. Jean-Guy cuffs the RCMP agent to a pew until the local police arrive to arrest him. After they do, Armand cleans up at home and fills an aspirin bottle with Three Pines spring water. Armand returns to Charles’s parents’ house, and they finally admit that Charles left his notebooks there.

In Rome, Isabelle discovers that Brother Robert is dead and meets the other monk who has the chartreuse recipe. This monk tells her that Robert received articles about the murders that Armand thought were Mafia hits. One victim was Robert’s aunt, and the other was a stranger; both murders were meant to silence Robert. When Sebastien pulls a knife on Isabelle, she realizes that he’s involved in the plot to poison the drinking water. The monk making chartreuse hits Sebastien with a large recipe book.

Armand and Jean-Guy go to the water-treatment plant that Charles was killed for investigating. With the help of an engineer, Manon, Jean-Guy goes to the command center to shut down the plant. Armand goes to the pump rooms. There, David from the RCMP points a gun at Armand’s head. During the scuffle, Armand switches the aspirin bottle containing the poison with the one containing plain water. Jeanne shoots David as he shoots Armand. The poison doesn’t enter the water, and they shut down the plant.

David’s bullet only grazed Armand’s head but causes temporary hearing loss, and he struggles to communicate with his family and friends. He has nightmares about David asking him for Charles’s notebooks, which leads him to realize that the notebook alludes to another mystery about pollution, ending the book on a cliffhanger.