The season is summer. The scene is a remote lake in the French countryside where men meet for conversation, sunbathing and open-air sex. The theme is murder.

Setting his tight, restrained movie around a gay cruising hideaway gives director Alain Guiraudie a built-in rationale for intrigue. The beach is a place of apartness, mystery men seeking surreptitious encounters. Figures in a landscape, the men move stealthily, as if on the lam. Then one man kills another, while a third watches from a distance, hidden from murderer and victim. When an inspector arrives to investigate the drowning, the witness lies about what he has seen. He clearly has a yen for the handsome killer. And perhaps a death wish of his own.

The protagonist of “Stranger by the Lake” is Franck (Pierre Deladonchamps), whose voyeuristic passivity recalls the central character of Albert Camus’ “The Stranger,” another story of a senseless murder on a beach. Maybe the film’s stranger is the athletic killer Michel (Christophe Paou) or Henri (Patric d’Assumçao), a heavy-set loner who sits apart from the cruising beach, enjoying the lakeside quiet. Henri becomes Franck’s paternal confidant and Michel, the snake in this Edenic natural paradise, becomes his lover.

Guiraudie is explicit about sex; the director himself stripped to play one of the cruising spot’s regulars. But full frontal passion isn’t the movie’s focal point. It’s the knotty connection between untrammeled desire and danger. Franck is thrilled by the risk that Michel represents, though this hunky package of stranger danger is a very real threat to himself and the community.

The anxiety is palpable. Guiraudie cuts fairly slowly and stays far back except for dialogue scenes. He builds a mood of queasy deadpan tension from steadiness and silence. It’s an effective technique, but I chafed at the 97-minute film’s pacing. It is set over 10 days and occasionally seems to be proceeding in real time. There’s too much metaphysical packaging material in the story; it’s half Styrofoam peanuts. But its ideas are intriguing and its murky suspense is undeniable.