On paper, the new French film Petite Maman sounds like it could be a riff on Freaky Friday, Back to the Future, or 13 Going on 30. It’s the story of how a young girl, Nelly (Joséphine Sanz), comes to spend time with her mother, Marion (Gabrielle Sanz), at the same age. There is no time machine or magic talisman that allows this reunion to happen, which would distract from their precious moments together. Director and writer Céline Sciamma, who might be best known for the historical romance Portrait of a Lady on Fire, instead establishes a kind of realism that allows for regret, wistfulness, and, above all else, curiosity. There are so many moments where the film could become tedious or maudlin, but somehow Sciamma finds the right note and sticks with it.

A muted opening scene quickly establishes the kind of girl Nelly is. She dutifully walks from one room to another in what appears to be something like a hospital, saying “au revoir” to the older women who live there. They look at her with bittersweet surprise—Sciamma keeps Nelly in medium shot, the camera following like a concerned phantom. But not until we see the last room, do we realize what is happening: Nelly’s grandmother recently passed away, so she has no reason to visit the place where her grandmother spent her last days.

Nelly and her parents leave for her grandmother’s house, where they have some time to collect her things. This gives Nelly an opportunity to wander the adjacent woods—if she had worrywart parents, the film would fall apart—and in the woods she stumbles upon another young girl. Marion looks a lot like Nelly, and after speaking a few moments, Nelly realizes this other girl is her mother. For a while, anyway, she keeps this information to herself.

Joséphine’s performance—guarded, a little sad—tells the audience how to feel about the material. Once Nelly figures out what has happened, there is no great exclamation or concern that she is stuck in the past. She simply takes what she sees at face value, realizing this is an opportunity to learn more about her family. When the two girls return to Marion’s childhood home, everything looks different, as if people still live there. Nelly effectively time traveled, and she observes all the changes with the patient deliberation of an archeologist. Many scenes unfold with minimal dialogue, and because Sciamma’s camera lingers over Nelly’s silent reaction, the film invites us to think about our own families. It is easy enough for Nelly to return to her own timeline, and once Sciamma establishes the rules of her fantastical premise, we are free to focus on the relationships in the past and present.

Shortly after Nelly and Marion’s first visit, Nelly’s adult mother (Nina Meurisse) departs the house, leaving her father (Stéphane Varupenne) to watch over her. This is a shrewd storytelling and filmmaking decision, since it prevents Nelly and the audience from comparing two actors who play the same character. It also adds to the subtext of grief: Nelly misses her grandmother terribly, and silently intuits that her mother is experiencing death in a deeper, more painful way. Sciamma implies Nelly’s mother suffers from depression, but never says the word, leaving the other characters to worry and keep a respectful distance.

After a few days together, Nelly grows more trusting of Marion, directing their conversation in such a way that she can ask revealing questions, albeit in an oblique way. Sciamma lets the dialogue get a little precocious here, as no eight-year-old has this level of wisdom, yet her control of tone smooths over any implausibility. She also suggests Nelly and Marion are unusual for their age, namely through a game of make-believe where they imagine a melodramatic murder mystery together.

As actual sisters, Joséphine and Gabrielle Sanz are fascinating because of where their similarities begin and end. How did Sciamma get such pitch-perfect performances out of them? Do the young actors fully understand the implications of each scene? Petite Maman offers few direct answers, and opts for an ephemeral feeling where everyone seems safe, and anything is possible. Toward the end of its brief runtime, the film concludes with Nelly and her mother understanding more about each other and being closer for it, including an ambiguous final exchange that suggests we may learn more from multiple viewings. Either way, it is rare for a high-concept film to be this quiet, involving, and conclude with a seemingly effortless sense of emotional satisfaction.

Petite Maman opens in area theaters on May 6.