“It’s misfiring,” Felix tells Leon while they’re still on the road. “I can’t hear it,” Leon replies. That exchange aptly sums up what will become a sojourn fraught with mixed signals, low-key anxiety and thwarted desires, all of which have to do with Leon’s inability to fully engage with the world around him. Once the pair have arrived at the idyllic thatch-roofed cottage, they discover they will have a roommate: Nadja (Paula Beer), a blithely gamine young woman who becomes an object of fascination for the saturnine, self-absorbed Leon. Annoyed by the intrusion, sleep-deprived thanks to Nadja’s noisy lovemaking with an unseen partner in the next room, trying desperately to work while Felix fiddles around the house and goes swimming in the ocean, Leon becomes progressively grumpier. As a cinematic archetype, he’s a classic: the blocked, displaced writer who becomes obsessed with an attractive stranger against the seductive backdrop of sun, summer and endless bottles of wine.

Inspired by the seasonal movies of Éric Rohmer (and, just maybe, the 1969 French classic “La Piscine”), Petzold brings his distinctively restrained, classical style to a story that evokes equal measures of pleasure and unease. While news of a forest fire threatens to destabilize the group — which becomes a foursome with the addition of a local lifeguard named Devid (Enno Trebs) — the real tension comes from Leon, whose gaze at Nadja communicates longing, hostility, resentment and admiration all at the same time. Spontaneous, untroubled and direct, Nadja teeters perilously close to becoming the kind of free-spirit muse that has morphed into the Manic Pixie Dream Girl cliché. Luckily, Petzold pulls her back from the brink of insufferability with one whopper among many in a twisty third act.

Beer, a frequent Petzold collaborator, has the kind of face the camera loves, and it’s easy to see why Leon develops such a fascination with her; for his part, Schubert never tries too hard to make the audience love Leon, which cuts both ways: Moody, defensive and obnoxiously solipsistic, he would be impossible to care about were it not for the loneliness and insecurity Schubert embodies with such nuanced subtlety.

With literal and figurative disasters looming, “Afire” asks the eternal question of whether the problems of two — or three, or four or even five — little people amount to a hill of beans in this pre-apocalyptic world. Ever the humanist, Petzold makes note of the costs of denial, before finally casting his lot with the yeasayers. Richly observed and paced with relaxed, unforced ease, “Afire” doesn’t ignite as much as smolder. It’s a slow, steady burn.

Unrated. At the Angelika Film Center Mosaic. Contains coarse language, smoking and sexual references. In German with subtitles. 103 minutes.