One of the best things about watching a lot of movies for a living is that occasional joyous thrill of sitting in a darkened theater being overwhelmed by a film, and knowing immediately that, without a doubt, you've just seen something that will absolutely end up on your top ten of the year. When that film is written and directed by a first-time director, it's even better, because you know you've just been witness to the start of a film career that promises to be something special. French novelist-turned-director Phillipe Claudel's much-talked about freshman effort, I've Loved You So Long, which has its North American premiere last night here at Telluride following an award-winning showing at Berlin and a hugely successful run in France, is one of those films.

The film, which stars Kristin Scott Thomas, opens with the reunion of two sisters who haven't seen each other in 15 years. The opening credit sequence goes back and forth between Juliette (Thomas), sitting alone at a table in an airport, looking as lost and desolate as a war refugee, and younger sister Lea (Elsa Zylberstein), coming to pick Juliette up, nervously dropping her keys as she walks in. Without a single word of dialogue to enlighten us as to what's wrong with Juliette, we know this much: this is a woman who has suffered some horrific trauma; she is lost to herself, locked away, not there.

We learn soon enough that Juliette has just been released from prison after serving 15 years for murder, and that Lea, who was just a young girl when her adored older sister disappeared from her life, is bringing Juliette to her home to reconnect with her after all these years. There's tension between Lea and her husband, Luc, who's uncertain about the wisdom of Lea bringing her sister into their home, which they share with their two young daughters and his father, and from Juliette, who doesn't want to be in their lives and seems to have lost all sense of how to connect emotionally with others, but knows she doesn't really have a choice but to be there. Juliette may have been released from prison by the authorities who put her there, but she's still very much a prisoner within herself.

The older of Juliette's young nieces is fascinated by the sudden appearance of the aunt she never knew she had, and peppers her with questions about where she's been all this time. Juliette's tension when she's engaged in conversations with the child is palpable, but try as she might to keep her emotional distance, her niece's persistance and the normal routine of family life slowly starts to break through her walls.

And that's as much as you're going to get out of me as to the plot of this film, because you simply have to see it yourself to appreciate the masterful way in which Claudel weaves this story together. At its deepest level, this is a story about prisons, in which we never see the walls of a prison cell. It's about the ways in which we lock ourselves up, punish ourselves, give up and turn our backs on the world when the pain it deals us is more than we can bear, but it's also about the resiliency of the human spirit, and of love to heal us even when we've given up all hope.

Claudel talked in the Q&A after last night's screening about the ideas underlying his script, and about how when an audience watches a movie, they see what is "within the borders" -- that is, what the director chooses to frame on the screen -- but they're also seeing in their minds all the things implied and the things they as individuals infer from what they're seeing, creating a backstory in their minds that plays simultaneously with what they're watching. In I've Loved You So Long, this aspect of the interplay between audience and screen, between the filmmaker's vision and what the viewer brings to it, is much of what creates the delicious tension you feel while watching it -- and the powerful emotional release at the end when Claudel ties all the pieces together.

As you're watching the film, you're not entirely sure if you want to like Juliette, particularly when it's revealed why she was in prison for 15 years. Claudel sets up a situation where the protagonist is both fragile, which makes you feel empathy for her and want to like her, and repellant, in that what we know of why she was locked away for 15 years is so terrible, so repugnant, that we feel ourselves draw instinctively away from her. Lea, as the younger sister who's both overjoyed to reconnect with her lost sister and repelled by the crime that's kept them apart, serves as the audience's fictional proxy, the person through whom we view and judge Juliette.

Claudel's script is a masterpiece deserving of a Best Original Screenplay Oscar -- there are a many moments in this film where a little reveal just overwhelms you with its emotional impact, and the narrative structure is very nearly perfect -- but it's the symbiosis of script with acting that translates that story so powerfully to the screen. Claudel creates the character arcs in his story with surgical precision, but the performances of Thomas and Zlyberstein breathe life into the narrative structure to make us feel the emotional weight of the story.

Thomas's performance here has been generating Oscar buzz for a while now, and deservedly so; she will almost certainly garner a Best Actress Oscar nod for this film. But it would be unfair to overlook Zylberstein, who's well-known in France but less so in the United States; she more than holds her own with Thomas, and it's the emotional relationship and tension between these sisters that drives the film. She's equally deserving of accolades for this role, and I hope that she'll get the recognition she merits.

I've Loved You So Long is art at the level that makes independent cinema worthwhile. In the best of film as art, we connect with the story and the characters on a deep level; we watch the characters' lives and stories unfold, we make judgements and feel emotions, and we ponder the reactions the film evokes in us, learning something about ourselves and our values in the process. Like The Lives of Others, which also played a Telluride a couple years ago before going on to earn Oscar nods and mentions on many end-of-year critics' lists, I've Loved You So Long is that rare masterpiece of a film that will live within your soul long after the closing credits have rolled.

I've Loved You So Long will play at the upcoming Toronto International Film Festival.