The following version of the novel was used to create this study guide: Penny, Louise. Glass Houses. Minotaur Books, August 29, 2017. Kindle.

In Glass Houses by Louise Penny, the Sûreté’s Chief Superintendent Armand Gamache had to fight his own conscience as he tried to rebuild the law enforcement department and make Québec safer by bringing down large drug cartels. In order to make progress, Gamache had to make calls that he knew would have devastating consequences not only on his own career, but on the careers of others and the lives of strangers. Gamache tried to reason that the end results would outweigh the costs he would have to pay.

It was the appearance of a black-robed figure on the village green in Three Pines that alerted Gamache there was danger coming. Gamache and his second-in-command, Jean-Guy Beauvoir learned that the figure was a cobrador, a person who came to provoke the conscience of a person who had committed a crime but never been punished for it. No one was sure why the cobrador had come, but they were relieved when he disappeared after a few days.

The day after the cobrador disappeared, however, Reine-Marie, Gamache’s wife found a person dressed in the cobrador’s costume in the basement of the church. That person was dead. Investigators discovered the dead person was Katie Evans, a woman who had come to Three Pines with her friends on a yearly reunion. No one seemed to know why Katie had been killed or who might have killed her. Investigators were also baffled because Reine-Marie did not mention having seen a bloody bat in the small room where she had found Katie’s body. When investigators first saw the scene, the bat was prominent. They could not understand how the bat had been returned to the murder scene or why it had been returned. The bat was the key that led Gamache to realize the church, which had once been used for rum-running during the Prohibition, was being used in the modern drug trade. He discovered a secret door in the small room where Katie’s body was found the led directly to the wood near the Canadian-American border.

Meanwhile, Gamache and his officers were biding their time and trying to appear incompetent as they led the leader of a major drug cartel into a trap. Gamache knew they were losing the war on drugs and could only make any progress by making a major hit. Penny alternates scenes from the trial against Katie’s murderer with scenes at the time of Katie’s murder as she details how Gamache developed his plan to trick the drug cartel leader into complacency. She also describes how Gamache committed perjury when he lied on the stand about the baseball bat and its placement in order to keep the drug cartel from knowing the officers were wise to them.

At the end of the novel, Gamache, Beauvoir and the other officers were successful in their fight against the drug cartels. Even though Gamache was praised for going against the law and following his own conscience, he was relieved of duty and forced to undergo an investigation.

Gamache also discovered that Katie’s murder was motivated by the death of her college boyfriend, Edouard. Edouard had been high on drugs and had jumped from the roof of his college dorm after Katie broke up with him. Katie and Edouard’s other friends blamed his death on the man who sold Edouard the drugs. Edouard’s sister, however, blamed Katie. She killed Katie in an attempt to get revenge for her brother’s murder.