Grade: 4.5/5.0

“Shiva Baby” opens with a sex scene; the action is out of focus, which means it’s easier to hear Danielle (Rachel Sennott) and her sugar daddy Max (Danny Deferrari) than it is to see them. As their breathing gets heavier and louder, the moans begin to subside, and the motion slows. Writer-director Emma Seligman is ruefully clever to open her movie with an orgasm — a moment of relief and completion — because the rest of “Shiva Baby” is a roller coaster of anxiety, deftly building tension and winding up its audience without reprieve. And it’s fantastic.

Danielle is a college student on the cusp of graduation with no fixed plans for the future. On the side, she performs sex work to make a little money. At the beginning of the film, she joins her family in attending a shiva, parrying the same intimidating questions from relatives and family friends about her plans after graduation. The situation sours when Danielle sees her accomplished ex-girlfriend Maya (Molly Gordon), but it spoils entirely when she notices Max with his heretofore unmentioned non-Jewish wife, Kim (Dianna Agron) — oh, they also have a baby.

The marvel of “Shiva Baby” lies in its ability to awaken excruciating tension in a mundane circumstance. The room feels tightly bound from the camera’s cross-cutting between speakers in the conversation. Amid the quick dialogue, the camera lurches in and out of focus, creating seasickness that gives the whole movie a growing sense of unease. Ariel Marx’s score has a recurrent motif of plucked guitar strings, which resembles the ticks of a time bomb and are punctuated by the frequent cries of Max and Kim’s wailing baby. The film keeps viewers on edge as Danielle does damage control in real time to keep the landmines in her life from exploding.

As the star, Sennott steers the film tremendously. Seligman’s writing is sharp as a tack, and the leading actress brilliantly squares the script’s levity and witty quips with her character’s kinetic anxiety. Sennott makes Danielle devilish in all the right ways; she lies through her teeth, eavesdrops as she eats lox and makes the audience root for her. Sennott’s expressions, in particular, are remarkable, often funny portraits of performative politeness underscored by quiet stress. Her performance cleverly endears a character whose flaws, in the wrong hands, could have overpowered and ruined the movie.

Fortunately, Sennott is not alone: The performances in “Shiva Baby” are all-around strong, which is as much of a triumph for Seligman as it is for the actors. Because of the film’s thrilling pace, the characters in “Shiva Baby” bring a different perspective to the stereotypes about Jewish relatives being intrusive, overbearing or irrational. In this way, Polly Draper as Danielle’s mother, Debbie, is funny, frank and loving, a noteworthy standout for both her comedic and dramatic chops. Seligman creates fully realized characters whose Jewish identities are integral to the story, and the film soars because its actors totally understand the assignment.

“Shiva Baby” handles Danielle’s sexuality thoughtfully. She is, indeed, a chaotic bisexual, but Danielle’s general messiness isn’t framed as a product of her sexuality. While sharing its importance, the film gives this part of Danielle’s identity room, and it doesn’t dominate her entire character. The film’s reality heightens as the narrative tensions swell, but the relationship between Danielle and her mother, Danielle and Maya is underpinned by the reality of what it’s like to be young and queer. In one instance, Danielle’s mother rattles off the line: “Oh, I lived in New York in the ’80s. You don’t have to explain anything to me.” Yet, in the same stroke, Danielle fends off dismissive comments about “experimenting.” Seligman portrays an all-too-familiar reality for reality bi women, fleshing out sexuality with humor and nuance.

On the surface, “Shiva Baby” seems like a wry dramedy with a fresh premise. Yet, as the film unfolds, it bends over its own genre, churning out a feature-length anxiety attack that also happens to be really, really funny.