A new movie written and directed by Spanish filmmakers Marisa Crespo and Moises Romera, “You Are Not Me” is Christmas-themed entertainment that should probably be avoided during the holiday season. There’s not a merry tiding or a ho-ho-ho to be gleaned from their debut feature, an unsettling psychological thriller.

Ms. Crespo and Mr. Romera’s movie takes place on Christmas Eve and centers not only on the dynamics of family, but the tensions that can accrue from class and cultural differences. It’s a cunningly crafted, if sometimes spottily plotted, picture that is far removed from Frank Capra’s “It’s A Wonderful Life” (1946) or George Seaton ‘s “Miracle on 34th Street” (1947). 

Which isn’t to say that “You Are Not Me” doesn’t share certain commonalities with these holiday staples: The supernatural is touched upon as is the good will that arrives on Christmas morning. Still, tread lightly, as Ms. Crespo and Mr. Romera’s film trades feel-good homilies for desperate measures. Edgar Allan Poe, Luis Buñuel, and Roman Polanski’s “Rosemary’s Baby” (1968) are touchstones here, as are the doings of the Bohemian Club, that patriarchal enclave situated about an hour-and-a-half outside of San Francisco where, as per the Washington Post, “the rich and powerful go to misbehave.” 

Having read a BBC article about Bohemian Grove, Ms. Crespo and Mr. Romera describe how this setting “simply hide[s] a handful of rich people who aspire to relate to people of their status and talk about their business by going around among equals. Or maybe not. …” It’s that qualifier that served as the prompt for “You Are Not Me.”

Aitana (Roser Tapias) is a 30-something doctor working for an NGO in Brazil. She’s visiting Spain to celebrate the holidays with family and is traveling with her wife Dori (Yapoena Silva) and their recently adopted son João (a beyond adorable Boubcar Djitte Silla). They were set to arrive on the eve of the new year, but Aitana has decided on a surprise Christmas gift for her mother, father, and younger brother: showing up unannounced on December 24th with daughter-in-law and grandson in tow. It’s been three years since she’s been home; how could it not be a happy reunion?

It’s not. Aitana, Dori, and João arrive at a luxe and rambling estate — this is clearly a moneyed family — and Aitana pretends to call from faraway Brazil even as she rings the doorbell. After an awkward moment or two, an unknown middle-aged woman comes to the front gate and events become even more awkward. Pepita (Pilar Martínez), she tells the weary travelers, is a friend of Aitana’s mother, Oriol (Álvaro Báguena). The travelers enter the house only after Aitana does some strong-arming. Things are decidedly off.

Once inside, the response isn’t any less querulous. Oriol is polite upon receiving her daughter. Her husband Justo (Alfred Picó) isn’t polite at all: He’s clearly put out by the early arrivals. The only person happy to see our visitors is brother Saúl (Jorge Motos), who is confined to a wheelchair because of a neurodegenerative disorder. Pepita’s husband Oriol (Álvaro Báguena) introduces himself and is impressively suave. As for Pepita: She shares a libation of her own concoction with the guests, failing in her efforts to ease the tension in the room.

Aitana’s puzzlement is amplified upon discovering a woman sleeping in her childhood room: Meet Nadia (Anna Kurika), Saúl’s current caregiver. Justo and Oriol, we learn, found her sleeping on the doorstep seven months back, destitute and with no place to stay. They subsequently provided Nadia a place to sleep out back and, eventually, invited her to live in the home; she’s proved herself an honest soul and a diligent worker. The odd thing isn’t how much Nadia has ingratiated herself to the family, but, rather, how the family has taken her into its arms. Oriol and, especially, Justo treat Nadia with a deference that they don’t proffer to their biological daughter.

At which point, this story of familial discord takes some head-scratching turns, all the while maintaining an ominous sense of displacement and disappointment. The culminating event is a dinner party dominated by an older crowd of well-to-do strangers, and if genre enthusiasts will likely intuit the destination to which the film is headed, that doesn’t make the efforts of Ms. Crespo and Mr. Romera any less convincing or eerie. 

If anything, the ending that occurs on Christmas morning is spot-on in terms of just how unnerving narrative suggestion can be. “You Are Not Me” is a sly film that should be enjoyed only after the decorations have been taken down.