Writer-director Tilman Singer follows his possession chiller, ‘Luz,’ with a stay at a German Alpine vacation resort that uncovers a nightmarish breeding conspiracy.

Ornithologists will no doubt roll their eyes and scoff, “Who doesn’t know that?” But it was news to me that cuckoos, aside from inspiring those infernal kitsch clocks you want to smash once an hour, are also what’s known as brood parasites. That means they’re either too busy or too lazy or too evil to raise their own young, so they drop their eggs in the nests of other birds and let them do the parenting instead. Respect. German writer-director Tilman Singer folds that fascinating nugget of bird arcana into a reproductive horror scenario that’s more strange than coherent in his second feature, naturally titled Cuckoo.

At its best, the movie is kind of like The Stepford Wives meets Rosemary’s Baby, with side orders of Cronenberg, J-Horror and Lynch. The mixed-bag 2021 film False Positive, with Ilana Glazer, Justin Theroux and Pierce Brosnan, took a more clinical route to a comparable nightmare in which men seek to control women’s reproductive systems.

The other big plus in Cuckoo’s favor is the magnetic Hunter Schafer, making good on the promise of her work on Euphoria in her first big-screen lead role, in ways that her supporting turn in the Hunger Games prequel could only tease. Finding an ideal balance between vulnerability and sharp survival instincts, the rangy style icon is a commanding presence as Gretchen, an American about to turn 18 and seriously underwhelmed to leave behind her friends and the home she loves to go live in the German Alps with her dad Luis (Márton Csókás) and his new family. Anyone who doesn’t guess instantly about the reality behind Gretchen’s calls home to her mother has probably never seen a horror movie.

Gretchen feels no connection either to her father’s new wife, Beth (Jessica Henwick), or Beth’s 7-year-old daughter, Alma (Mimi Lieu). She finds it tedious that Alma is mute and only communicates with gestures or a voice app, though she does give her stepsister points for having eaten her sibling in utero, in a case of Vanishing Twin Syndrome. Whether that’s essential to the plot or just another bit of cool weirdness thrown in for the heck of it is open to debate.

Singer nails the intriguing set-up as the not-quite-blended family is greeted by Alpine resort owner Herr König (Stevens), who will be Luis’ new boss in a project to expand the guest accommodations. König is a creep for the ages, and Stevens has a lip-smacking good time being solicitous but casually skeevy with Gretchen while showing an inordinate interest in Alma. The family’s new home is inviting enough, but something about the place and everyone in it is a little off.

Cycling home from work at night against König’s advice, Gretchen is pursued by a scary hooded woman (Kalin Morrow). She sustains a head injury while seeking refuge at the local hospital, where Alma has been admitted following a seizure. The head medic, Dr. Bonomo (Proschat Madani), is no reassuring presence; she’s indebted to König, who funded the chronic disease center that she runs. Gretchen also meets Henry Landau (Jan Bluthardt), who claims to be a detective investigating strange occurrences in the area.

It emerges that Luis and Beth first met König when they honeymooned at the resort eight years earlier, and the chumminess of the two men suggests that Gretchen’s father might be in on the nefarious plan. That would also seem to apply less ambiguously to police officer Erik.

The atmosphere is sufficiently unsettling to make Gretchen flee when the opportunity presents itself with flirty resort guest Ed (Àstrid Bergès-Frisbey), who wants to take her to Paris. But that escape attempt ends badly when the hooded woman’s appearance on the road causes an accident. Badly banged up and back in hospital, Gretchen finds herself with only Landau and her trusty switchblade as allies once König starts making ominous pronouncements like, “The adolescent needs to be trained.”