Maja is a Danish actress who has found a new love, but who comes to realize her “Attachment” isn’t the one that rules her new lover’s life in this thriller that dabbles in Jewish supernaturalism.

It’s a mysterious, quietly suspenseful war of wills romance that builds towards revealing whatever is bothering Maja’s new love’s quite conservative if not quite Orthodox mother. And if this Danish film fizzles and fades away rather than delivering a big, harrowing climax, at least it succeeds in creeping us out with more genre reminders that Judaism has its own “Exorcist” traditions and its own versions of the demons that haunt the traditions of most every culture, and every religion.

Josephine Park, best-known from her many Danish TV appearances, is Maja, a Copenhagen actress who used to get work, now in her mid-30s and reduced to acting out book characters in Danish libraries.

That’s how she meets the British grad student Leah (Ellie Kendrick). They tumble from a classic “meet cute” into a passionate affair, one Maja can’t bear to give up when Leah heads home. She abruptly flies with Leah back to London, back to the flat that’s just upstairs from Leah’s brusque, domineering mother, Chana (Sofie Gråbøl).

But Maja noticed that Leah sleepwalks back in Denmark. Then a seizure caused her to break her ankle. And now, Leah’s hovering mom is coming between them with phrases that set off alarm bells — “It’s too much for you alone.” Wear this amulet or drink that soup “for your own good.”

There are noises in the house at night, and Chana’s superstitions — leaving a particular type of candle lit, spreading salt along the walls, drilling a hole and rolling up a prayer to hide inside it — are a bit much.

That’s a clever touch in writer-director Gabriel Bier Gislason’s script, making Maja our surrogate, assuming that all we know about “Jewish mysticism,” “kabbala,” is what Maja knows.

“It’s the Madonna thing, right?”

Maja stumbles into an Orthodox bookstore whose “goy” avoiding owner (David Dencik) dials down the rudeness and starts explaining “golems” and “Dybbuk” to the out-of-her-depth Dane.

There’s something going on in that house, something that might explain why Leah’s dad fled, that pertains to her seizures and her mother referring to them as “funny little episodes.”

The “war of wills” lets us question just how accepting of her daughter’s sexuality Chana is while skimming over the much-older Dane’s connection to the early 20s grad student.

The film’s foreshadowing could not be more obvious, but it teases out the source of the “problem” adeptly enough to keep some of us guessing into the drab and over-explained finale.

“Attachment” doesn’t reinvent “possession” movies, and isn’t even the first of these to dabble in Jewish traditions and rituals and demonology.

But good performances, light touches in a movie with a gloomy tone, a romance we buy perhaps because of its impulsive “U-Haul Lesbian” cliche and a struggle in which we see real stakes make this familiarly-unfamiliar thriller work.

Rating: unrated, violence, sexual situations, profanity

Cast: Josephine Park, Ellie Kendrick, David Dencik and Sofie Gråbøl

Credits: Scripted and directed by Gabriel Bier Gislason. A Shudder release.

Running time: 1:45