Stephanie Daley is the strongest proof I've seen this year that the Sundance Lab – designed to give emerging filmmakers the creative and financial support they need to raise their game – is doing something right. The film is beautifully – and by all appearances expensively – shot, and its cast (toplined by executive producer Tilda Swinton and Amber Tamblyn, whose rabid Joan of Arcadia fanbase surely helped to get this film made) is full of name actors, and from afar it has every visual marker of a high-gloss, commercial thriller. But writer-director Hilary Brougher (she was last here in 1997, with her debut, The Sticky Fingers of Time) has hardly made a Hollywood confection. Daley is essentially a non-linear case study of the psychological swirl around two parellel pregnancies: that of Lydie, a 40-ish forensic psychologist whose marriage and psyche are still recovering from a stillbirth, and the mysterious case of the title character (Tamblyn), a high schooler on trial for throwing her newborn daughter in a trash can. Right before her scheduled pregnancy leave, Lydie is asked by the prosecutor's office to conduct a series of examinations with Stephanie, who claims innocence and refuses to take a plea deal. It's Liddy's job to get Stephanie to talk, and the young girl's story, told through flashback, is woven through the older woman's trepidatious third trimester, as she worries for health, doubts her husband's fidelity, and tries to come to terms with the child she's already lost. The material, in different hands, could have easily have drifted into Lifetime movie territory, but Brougher brings a fearless spirit to the thing. There's a rawness to Stephanie Daley that we rarely see in American film – it paints slick composition and beautiful, bleeding color on the kind of story about sex and faith that no one has told well since before Lars Von Trier decided to tackle American imperialism with Brechtian critique.

Before the events in question, Stephanie's only tragedy is that she's sadly ordinary. A shy but precocious teen, she's young enough to still feel bound to her religious mother and internet-addict father, but just old enough to start pursuing an urgent curiosity about sex. One summer night, she follows "faster" friend Rhana (The Squid and the Whale's Halley Feiffer, again doing impeccably natural work) to a party. A friend of a friend of a friend's parents are out of town; an older brother has picked up a keg; and Stephanie has tarted herself up in eyeshadow and miniskirt, more to impress Rhana than any particular boy. Add in Stephanie's simultaneous desperate need to be touched, and near total sexual naivety, and it's not hard to imagine what's going to happen when the cute boy manning the keg cocks his head and asks her name. Sure enough, there's an empty master bedroom upstairs, and sure enough, young Cory wants to do more than kiss. Stephanie's deflowering comes to an end with a loud pounding on the door – another pair of young "lovers" want their turn – and with those ever-assuring three little words from the mouth of her suitor: "I didn't come." Nine months later, on a school ski trip, she's collapsed from blood loss in the snow; five months after that, she's pushed to Liddy's door.
Stephanie's story seems to change slightly every time she shows up for forensic analysis. In the film's best conundrum, we have to wonder: is she crazy – or is she just a teen? When so much of your daily existence, navigating teachers and friends and boys and parents – all of which Brougher wisely shows just enough of to humanize Stephanie, without ever explaining her –  revolves around pretending to be something and/or someone you're not, it takes a certain kind of skill to unpeel your layers and know which ones to throw out.

Luckily, Lydie is a born unpeeler. It's clear very early on that Lydie and Stephanie are spiritual opposites: one is propelled by faith and feeeling. the other, thinking and science. It would seem a simple enough dilemma – if there's anyone who can untangle the God-basted lump of hormones and lies that sits before her, it's a woman so unsentimental that she was ready to conceive almost immediately after cremating a stillborn child. And, refreshingly, Lydie has relatively confident that she'll be able to get Stephanie to tell her story. She isn't a Law and Order-style, manic career woman, working all hours of the night in order to uncrack the code. She wouldn't have the time – her own life requires too much emotional energy. Her marriage is both dependent on and crushing under the weight of her pregnancy, and just as she suspects her husband of cheating, she simultaneously finds herself drawn to a male friend. She's not a woman without faith, but that faith is very secular, grounded very specifically in patterned behavoir. To that end, when she finds a single, diamond earring in the catbox, it's the pea under the mattress that causes her thin resolve to slip.

People will surely talk about the labor scene, which is as gut wrenching and emotionally draining as anything I've ever seen. But the takeaway image of the scene – and the film – is a long, agonizing shot of Tamblyn's face, seen through the cracks between the wall and door of a public restroom stall. if you walked into the theater by mistake during that shot, you'd think you'd stepped into a horror film. When you fully grasp the weight of what Brougher has put her heroine through, you realise that you're not far off.