“Meanwhile on Earth” is a mysterious, mournful sci-fi film that upends expectations at every turn.

Grief is a beast that can drive a person to do monstrous things, and it assumes an otherworldly form in Meanwhile on Earth, a startling drama from Jérémy Clapin, the acclaimed French director of 2019’s I Lost My Body. Mixing live-action and animation to tell the tale of a young woman whose anguish over her sibling’s disappearance makes her vulnerable to the manipulations of a seemingly nefarious force, the filmmaker’s sophomore feature, which hits theaters Nov. 8, is part horror, part science fiction, and altogether idiosyncratic. Resembling an ethereal and despondent companion piece to Jonathan Glazer’s Under the Skin, it’s a genre effort that’s off the beaten path—even if an invisible path is precisely what its protagonist traverses.

Over an image of a space craft’s empty corridor, a man and a woman discuss what he’ll miss most about Earth during his voyage. The answer he gives is “a warm fireplace and a good beer,” but he soon reveals that it’s really his sister Elsa. Three years later, Elsa (Megan Northam) works at a senior living facility caring for the elderly, be it washing them with a wet hand towel or cutting up their food and feeding it to them in the cafeteria. On her daily commute, she drives by a statue of her astronaut brother Franck, who vanished on his intergalactic mission, and at night, she decorates it with a spray-painted “F”—a practice that, during a later conversation with her father, turns out to be a recurring one.

Northam has a face that’s at once sorrowful and steely, as if her sadness might transform into violence at any moment, and her blonde hair includes two long braids that sharply frame her visage. Though it’s clear that she’s in a state of suspended mourning, Elsa is almost as mysterious as the fate of her brother, and the actress’ hard-bitten performance is the alluring center of Meanwhile on Earth.

As she goes about her day-to-day, Elsa sketches virtually everyone she meets in her logbook, which she intends to use as the basis for a forthcoming comic that she can show to Franck—to clue him in to what took place while he was gone—when he comes home. Such hope, however, is shared by no one else in her orbit, including her father Daniel (Sam Louwyck), who sits in his basement pretending to play piano along to his records, or her mother Annick (Catherine Salée), who’s also her boss.

Elsa gets in trouble with Annick when she says that one patient is “stable in his decline,” and the description applies to her too. Sitting on a hill one evening with her younger brother Vincent (Roman Williams), Elsa believes she hears a voice behind her coming from a rickety antenna blowing in the wind. Following her attendance at a disorienting house party and an encounter with a homeless woman who tells her, “Your veins are showing,” she visits that same spot and discovers that particles and debris are swirling in a mini-vortex near the ground (which, full of rocks, resembles an alien landscape). Then, to her great surprise, Elsa hears the voice of Franck (Sébastien Pouderoux), who informs her that his ship floated away and he’s now all alone. More ominously, he warns, “Shh. They’re here. They float. They watch me. It’s everywhere.”

Franck explains that there’s a path and, depending on Elsa’s behavior, “they” can bring him back. Stranger still, he has her find a translucent seed growing in the nearby ground. When she puts it in her ear, it functions as an organic AirPod, and when she blacks out and subsequently comes to in her bedroom, she learns that it’s now taken root in her auditory canal. Worse, another voice (Dimitri Doré)—female, and coldly dispassionate—speaks to Elsa through it, informing her that she and her four extraterrestrial compatriots want to come to Earth, and that if Elsa walks the unseen forest path set before her, and provides these beings with human hosts to possess, they’ll return Franck to her. Enticed by this promise and terrified by the voice’s threats should she disobey or attempt to remove the seed, she agrees to carry out this task as the E.T.’s veritable hostage.

Meanwhile on Earth intersperses its action proper with animated interludes involving a male and female alien who fly across the surface of Saturn’s moon with the aid of a jetpack and, once they re-enter their ship, stare out at the galaxy. An air of disconnection and loss hangs over these passages, echoing Elsa’s own condition, and they afford Clapin with an opportunity to evocatively suggest his protagonist’s dreams and desires—and the hurt underscoring them—from an off-center angle. Those emotions are soon matched by panic and fury once Elsa follows the alien’s route through the woods, only to be stymied by a giant tree standing in her way. To deal with this, she visits her lumberjack friend Augustin (Nicolas Avinée), whom she convinces to chop it down for her. Unfortunately, Augustin’s coworker Jordan (Yoann Thibaut Mathias) accompanies them on this chore, and when Jordan gets violently inappropriate with Elsa, she’s forced to take gory measures to protect herself—the one instance the film tips into grindhouse-y territory.

Dan Levy’s score of downbeat electronica and doleful choir singing covers Meanwhile on Earth like a shroud, enhancing its sense of severe yearning, desperation, and estrangement. In its final third, the film—shot with lovely, lyrical ominousness by Robrecht Heyvaert—saddles Elsa with a moral conundrum, compelling her to choose between the safety of her brother and the lives of the innocent individuals she’d have to sacrifice in order to attain the reunion she covets. There’s suspense to that inner struggle, and also agony, and yet the writer/director upends narrative and tonal expectations to the end, refusing to indulge in the conventions (and payoffs) that might have rendered the proceedings more formulaic.

Elsa’s ordeal concludes not in the sort of brilliant light emitted by the film’s oft-spied stars, but at sunset, with bittersweet resignation over the fact that some journeys don’t have wholly satisfying destinations. Striking a sturdy balance between the straightforward and the oblique, Meanwhile on Earth charts its own peculiar and moving course through the grieving process.