The advance buzz on “The Origin of Evil” included passing references to Agatha Christie, the “Knives Out” films, “Succession,” and intimations of comedic intent — the latter of which were likely due to the film’s star, Laure Calamy. If it’s true that the first impression is the best impression — or, perhaps it is better said, the lasting impression — then Ms. Calamy will primarily be known to American audiences for her breakout turn as the ditzy Noémie Leclerc from “Call My Agent!,” the French television series about a talent agency and its many  tribulations.

“My Donkey, My Lover and I” (2020) built upon Ms. Calamy’s gift for comedy, and if “Full Time” (2021) saw the actress take a more serious turn as a single mom struggling to get by, the picture nonetheless benefited from the actress’s inherent likability. The same is true of “The Origin of Evil” — kind of. Even saying that much risks spoiling a film that is rife with spoilers, most of which are cunningly deployed. Director and screenwriter Sébastien Marnier is, in that regard, as sharp as he is understated.  

So, yes, we have a thriller that centers on a select group of squirrelly characters, an ensemble cast of seasoned actors, a mise en scène rife with privilege, and a plot peppered with twists, turns, betrayals, and ironies. In form, then, Mr. Marnier’s picture is standard-issue mystery material, albeit one that is less indebted to “The Murder of Roger Ackroyd” than the unseemly machinations typical of the novels of Ruth Rendell. Charm is in short supply. Nastiness is the rule.

Ms. Calamy is Stéphane, a single woman who ekes out a living by working at a fish cannery. When her landlady’s daughter moves back home, Stéphane scrambles to find a new living situation. Feeling desperate, she calls her estranged father. Stéphane is clearly uncomfortable doing so, as she and dad have never met: Stéphane was but one product of her father’s womanizing ways. Although Serge (a world-weary Jacques Weber) knew about Stéphane, he hasn’t had any contact with her.

Serge is a wealthy entrepreneur who lives in a mansion on the island of Porquerolles, an idyllic Mediterranean retreat. He’s ensconced there with his wife Louise (a been-there, seen-that Dominique Blanc), daughter George (Doria Tiller), granddaughter Jeanne (Céleste Brunnquell), and Agnes (Véronique Ruggia Saura), a housekeeper who is as formidable and as knowing as you might fear. Serge has had a run of health problems and George now oversees the family concern. She shows little compunction in letting her ailing father know just who it is that wears the business suit in the family.

Serge invites Stéphane to his home and their reunion is a tense affair. When Serge isn’t distracted, he’s beset by dizzy spells. Louise is the least diplomatic of hostesses, spouting whatever it is on her mind no matter how corruscating. George cuts a razor-sharp figure throughout the film. Agnes is tight-lipped but judgmental. Only Jeanne is untouched by the family’s bent for begrudgery, ruthlessness, and greed, but, then, she’s young. There’s always tomorrow.

At this point, a movie critic should stay mum. The machinations of Stéphane and company are the prime motivator of the picture and, of course, its abiding pleasure. If Mr. Marnier’s tweaking of narrative conventions isn’t particularly profound or idiosyncratic, its elisions are well-crafted, genuinely surprising, and often discomfiting. Should you favor ill-gotten gains, unlikely alliances, and justice for some but not for all, then “The Origin of Evil” is your cup of arsenic.