The latest from Louise Penny heads up our list of September's most thrilling suspense releases.

★All the Devils Are Here

Louise Penny's latest novel featuring Québec homicide inspector Armand Gamache, All the Devils Are Here, takes place in Paris, the City of Light, where he's awaiting the birth of his granddaughter. On the agenda are reunions with his son, Daniel; daughter, Annie; Annie's husband, Jean-Guy Beauvoir, once Gamache's second-in-command; and Stephen Horowitz, Gamache's nonagenarian godfather, a billionaire activist who has made a lot of enemies over the years. One of those enemies turns up early in the story, deliberately running the elderly man down at a Paris crosswalk as Stephen's friends watch in horror. Gamache and Beauvoir investigate the attempted murder, which local authorities are writing off as a simple hit-and-run, and there is much more afoot than meets the eye (please pardon my mixed metaphor). Beauvoir's new corporate job seems to have been offered to him as a result of intervention by Stephen, and Daniel has a potentially shaky investment linked to a man who now lies dead on the floor of Stephen's Paris pied-à-terre. Being Gamache and Beauvoir, they persist and prevail, in a sense, but not without taking some very serious hits along the way. Penny's books are always a cause for celebration, and this one is superb in every regard.

The Red Horse

During World War II, soldiers who experienced "shell shock" (the condition we now call PTSD) were often remanded to mental hospitals for treatment. James R. Benn's new Billy Boyle novel, The Red Horse, proves that rehabilitation was not always the featured item on the menu at such institutions. After a particularly harrowing set of adventures (chronicled in 2019's When Hell Struck Twelve), Billy and his friend Kaz have been sidelined in the Saint Albans Convalescent Hospital: Billy with uncontrollable shaking and daytime nightmares, and Kaz with a faulty heart valve. The pair jumps into the fray once again when Billy witnesses what appears to be a murder—two men in the clock tower engaging in some sort of argument or struggle, culminating in the death plunge of one and the disappearance of the other. A couple of additional homicides erase any lingering doubts Billy may have had about whether the first was an accident or deliberate. But there are forces at play in Saint Albans that seek to interfere with his mission, particularly when he happens upon clues that involve an enigmatic logo of a red horse. As is always the case with Benn's books, the painstaking research is evident, the story crackles with life, and the overlay of fictional characters onto very real historical events is seamless. If you are new to the series, welcome; there are 14 more to keep you busy after you finish this one.

The Killings at Kingfisher Hill

Author Sophie Hannah made a name for herself with clever, dark and intricately plotted standalone thrillers. Then in 2014, she was authorized to pen a series of novels featuring Hercule Poirot, the Belgian detective made famous by Dame Agatha Christie. It is no small undertaking to follow in the footsteps of Christie, but Hannah nails it in her latest, The Killings at Kingfisher Hill. The tone is pitch-perfect, the mystery aspect is as convoluted as anything ever crafted by Hannah's predecessor, there are more red herrings than you would find at a Swedish breakfast buffet, and the diminutive mustachioed Belgian detective has never been cannier. This time around, Poirot is summoned to an English estate to look into the murder of Frank Devonport, a country gentleman. The alleged killer (Helen, fiancée of Frank's brother, Richard) has confessed, but there is considerable doubt in the mind of her betrothed regarding her guilt. She will be hanged soon if no exculpatory evidence is unearthed. Who better to have on the case than Poirot, right? I am rarely a fan of series reboots, but Hannah's work is first-rate. Poirot lives.

One by One

Speaking of Christie, the legendary writer was known for her "locked-room" mysteries, a subgenre of suspense fiction in which the perpetrator could not have entered or exited the crime scene without detection, and yet somehow a crime was committed. Ruth Ware's latest work, One by One, updates this device. There's no stodgy English manor house here but rather a gorgeous, luxurious and very isolated chalet in the French Alps playing host to a millennial corporate retreat. The merrymakers are the founders and employees of emerging social media platform Snoop, an application that allows you to track the digital music listening preferences of your favorite celebrities and your circle of friends, with the caveat that they can track yours as well. When one of the group's members goes missing after an afternoon of skiing, a snowstorm and avalanche do double duty in isolating the already remote chalet—and then the guests start dying, one by one. Read this back to back with Christie's And Then There Were None, and you will witness the evolution of a literary form over the space of eight decades as Ware proves she's more than deserving of all those comparisons to the Queen of Crime.

In A Better Man, the sixth straight No. 1 New York Times best seller in the durable "Chief Inspector Armand Gamache" mysteries and the 15th title overall, Penny took Armand's story in refreshing new directions. No word yet on where this 16th series title is heading, but the 750,000-copy first printing speaks loud and clear.

Bestseller Penny's exceptional 16th series mystery (after 2019's A Better Man) takes Chief Insp. Armand Gamache, the head of homicide for the Sûreté du Québec, to Paris for the anticipated birth of a grandchild to his daughter, Annie, who moved to France with her husband, Jean-Guy Beauvoir, Gamache's longtime number two, after they both got jobs there. The happy reunion includes Gamache's son, Daniel, also lured to Paris by a job, and Gamache's godfather, billionaire Stephen Horowitz, who supported Gamache after he was orphaned. Tragedy strikes when Stephen, who made a career of exposing corporate wrongdoing, is hit by a delivery van while crossing the street, leaving him at death's door. Gamache, who witnessed the attack, tries to persuade the Prefect of Police, an old friend, that the hit-and-run should be treated as attempted murder, only succeeding after he finds the corpse of a stranger, who was shot twice, in Stephen's ransacked apartment. The tension rises as Gamache tries to investigate both crimes in a jurisdiction where he has no authority, and vital secrets about his family come to light, changing relationships forever. Penny's nuanced exploration of the human spirit continues to distinguish this brilliant series. Agent: David Gernert, Gernert Company. (Sept.)