Louise Penny’s twelfth Inspector Gamache/Three Pines Mystery, A Great Reckoning, is responsible for making Auntie M cry–twice.

That’s how movingly she writes and entwines readers with the characters they’ve come to know and love in the series, most especially Gamache and his extended family. And yet if a reader were to pick up this book and not know any of the history, they would still be impressed by the scope of its plot and the depth of the feeling she manages to wring out without any hint of melodramatic tricks–and to bring them to tears.

Gamache and his beloved Reine-Maire have retired to the little village of Three Pines, where both have accepted that retiring doesn’t mean eating croissants and sitting around the Bistro all day, but that they will find new work that interests them. For Reine-Marie, the former librarian at the National Archives Library becomes involved the historical society, organizing its papers and artifacts. For Gamache, after mulling over many offers, being courted for some and rejecting many, he’s accepted the role of Commander of the Surete Academy, the three year schooling for new police cadets. His goal is to clean the house of the former regime which sent out cruel and corrupt police.

To the surprise of everyone, including his wife, he invites an old friend who’s been living in exile to take a role as a professor, teaching the cadets how easily it is to be corrupted as he was. It’s an interesting concept, and one that will have personal and professional ramifications for the new Commander. At one time the two men were as close as brothers, until they took divided paths in their careers.

Gamache also deliberately leaves in place one corrupt instructor, believing him to be the mastermind behind a large financial swindle on top of corruption of the cadets. But he lacks enough concrete evidence to arrest him, nor does he have the name of the man’s accomplice. Serge Leduc had waited to be fired as so many of his colleagues were. Gamache openly explains his reasons to the man: he intends to find out the depth of his betrayal and to find his accomplice.

Then a professor is murdered, and four cadets who have been especially close to the man are the prime suspects. Gamache sends them to Three Pines to board there and gives them an unlikely assignment: find out the significance of an orienteering map found in the wall of the bistro that he’s been given as a gift, showing the tiny village along with other oddities. Is this work to keep the four occupied so he can observe them and find which one is a killer? Or is he trying to protect them from the killer? And is there more at hand, as a copy of that same map of Three Pines has been found in the professor’s effects.

Suddenly the list of possible suspects widens, and Gamache finds himself being scrutinized as a murder suspect. And what of his relationship with the tattooed and pierced cadet Amelia Choquet? Why is the angry and obstinate cadet being carefully groomed by the Commander? How does the map fit in, and what does it have to do with a stained glass window in Three Pines tiny chapel?

This is Penny at her complex plotting best, bringing all of the quilted threads of the story together in a satisfying and chilling climax. There is family time and high points, and many lows that Ganache must navigate. But now he has his son-in-law nearby, and a person he respects as Chief of Homicide of the Surety, his old job, in Isabelle Lacoste. But will he figure out the devious machinations of the killer before he strikes again–or worse, is arrested for the murder himself? Highly recommended.

A note to readers: Please take the time to read the Acknowledgements at the end of the book. For any author, and Auntie M knows this from experience, this is the time to express a personal and public thank you to readers and to the many people who help an author move his or her book from an idea to a reality to the one you hold in your hands or listen to or read on your Kindle. It this case, it is also clearly a love letter to Penny’s ill husband, Michael, and deserves to be read, both to honor him and his life, and to honor Penny and the wonderful and rich writing she continues to give her readers.