It is a very tough thing indeed to make a film that is at once restrained and brimming with feeling, a movie that could be fairly described as both big and small. It’s a wonder, then, that a first-time filmmaker, one whose main work is in the theater, could manage that feat so impressively. That’s what Celine Song has done with Past Lives, a dreamy, gently heartbreaking film that premiered here at the Sundance Film Festival on Saturday. 

Introducing the film before the premiere, Song told the audience that Past Lives is a very personal story. Like Song, the film’s protagonist, Nora (Greta Lee), is a New York City-based playwright who moved to Canada from Korea when she was a child. What else is personal about the film can really only be inferred, but the delicate care with which Song has constructed Past Lives suggests something closely held for years. 

The film is a triptych, beginning 24 years ago in Seoul, where Nora (then called Na Young, played by Seung Ah Moon) awaits her family’s impending migration to Toronto. She’s got a close pal, a budding sweetheart maybe, named Hae Sung (played as a child by Seung Min Yim, as an adult by Teo Yoo), who it seems will miss her dearly. Kids being kids, though, they don’t give themselves much of a goodbye. They simply part ways one day after walking home from school, and then the newly minted Nora is off to her new life. 

Song catches up with them 12 years later, then twentysomethings in the nascency of their adulthood. Nora has moved to New York City, pursuing her playwriting dreams, while Hae Sung has finished his mandatory stint in the army and is back home with his parents, working his way through engineering school. A chance Facebook encounter brings the two friends back together. This section of the film is near entirely a series of video chats, credible in their quotidian chatter but always humming with undertones of something larger, more meaningful. 

Past Lives is, befitting of Song’s profession, a talky movie, and is partly about the distances chasmed open and made smaller by language. Song manages to make this all cinematic; there is nothing stilted or stagey about the film’s long stretches of dialogue. It helps immensely that Song has a natural visual sensibility—the film, shot by Shabier Kirchner, is achingly beautiful, all watery blues and earthy greens and city light. The invaluable score, by Grizzly Bear’s Daniel Rossen and Christopher Bear, gracefully lilts around Hae Sung and Nora as they drift toward and away from one another. 

It’s in the third portion of the film, when Nora and Hae Sung are in their 30s, that Song calmly builds toward a breathtaking emotional payoff. Nora is married, to a kindly writer named Arthur (played by the indie-film pixie dust in human form known as John Magaro), while Hae Sung is newly out of a relationship and, perhaps, back to softly pining for his friend on the other side of the world. They finally meet, for the first time since they were kids, in New York. Nora shows Hae Sung the city while they talk around this thing that they share, until it can no longer go unaddressed.

Throughout the film, Song incorporates a Korean term, “In-Yun.” It’s a concept about human connection and, as the film’s title suggests, past lives. Through that idea, Nora and Hae Sung let themselves wonder about choice and destiny, chance and circumstance. Would they be together and in love had Nora not moved away all those years ago? But who would they be if she hadn’t? Surely not the people they are now. Maybe to change that history would, then, be its own kind of loss. 

Song’s film is about the resignation, the acceptance of lost things, that becomes a defining part of adulthood. Past Lives is also, subtly and poignantly, about the immigrant experience, what it is to leave one life behind—likely forever—in exchange for another. Past Lives is not concerned with regret. It is instead a thoughtful, humane rumination on what may be fixed in personal history but remains forever fluid in the mind. 

Grownup Nora and Hae Sung are, in some ways, still 12 years old. But in more and crucial ways, they are very much not. Their journey toward reconciling the facts of themselves, who they were and are, culminates in a pair of exquisitely moving scenes. Lee and Yoo are terrific throughout the film, nuanced and human and likable, but it’s in these closing moments that they are given a chance to truly shine. 

They so adeptly illustrate the quiet, cosmic yearning passing between these two characters: all of their wistful, pragmatic adult understanding mingling with an otherworldly sense that they are floating on the winds of fate. Past Lives is understated and yet vast in its consideration of the slow changes of life, of the past’s constant whispering to the present. The film is as auspicious a debut as one can hope to see at Sundance, the announcement of a filmmaker confident in her craft and abundantly generous with her heart.