If it’s never really occurred to you before what a strange word “custody” is, and how its two meanings — guardianship and imprisonment — are complementary yet also inherently at odds, be prepared to spend 90 gripping minutes constantly turning that over in your mind during Xavier Legrand‘s tense, terrifying film of that title. It starts with one kind of custody and ends with the implication of the other, yet throughout the film, places of refuge turn into besieged fortresses; protectors turn out to need protection, and a child’s would-be guardian becomes the very person he needs to be guarded against.

A talky but superbly performed prologue sets the tone for Legrand’s intelligent, understated approach. In a closed session, a judge hears the briskly outlined cases for and against the awarding of joint custody to the separated parents of a young boy, Julien (outstanding newcomer Thomas Gioria). His sister Josephine (Mathilde Auneveux) is about to turn 18 so she can make her own decisions, but Julien is a minor and his mother, Miriam (Lea Drucker), is hoping to bar his father, Antoine (an exceptional Denis Menochet), from any contact. She alleges violence and possessiveness. He counters that there is no real evidence. And when Julien’s own damning testimony, in which he says he does not want to spend time with his father, is read aloud in full, Antoine implies that it’s the product of Miriam’s brainwashing, murmuring “I don’t know what she says to him.”

Custody

But for the most part, Miriam, looking as exhausted as a rung-out cloth and Antoine, bearish and hulking and the only man in a room full of women, are silent as their lawyers advocate in clipped but emotive legalese on their behalf. It’s a mark of Legrand’s skillful writing that this scene appears to play out in real time, but is never less than involving, putting the audience in a similar position to the magistrate in that our feelings about the case swing first one way, then the other.

It’s an ambivalence that is subtly maintained for a while after Miriam receives news that the decision has gone against her and Antoine is to be allowed access to Julien. But gradually the tenor of their weekends together turns darker, before an explosion of temper over a dinner with Julien’s grandparents hints not only at the ungovernably volcanic anger that Antoine has been struggling to suppress, but also at where he might have got it from. Legrand does not seek to exculpate Antoine — indeed, as the film wears on he becomes progressively more monstrous. But he is not without compassion for the man inside the monster, just as there is, within every relationship destroyed by abuse, the heartbreaking kernel of the way things were supposed to be. Nobody, neither the eventual abuser nor the eventually abused, goes into a marriage hoping it will turn toxic.

Legrand’s restrained filmmaking, dressed down in DP Nathalie Durand‘s sober, unfussy imagery, beds the story into a very real sense of the ordinary. The drama unfolds among the tower blocks and trestle tables of lower-middle life (and incidentally gives Andrey Zvyagintsev‘s “Loveless” a rival for the year’s most affecting scene of a small blond boy wailing silently in distress in a gray, unlovely housing project). But this intense naturalism is also deceptive of the controlled way Legrand pivots and plays with point of view and perspective, maximizing each moment’s dramatic potential without resorting to unearned revelations. At times we’re seeing what Julien sees, at other times we’re with Antoine or Miriam. During one brilliantly staged, extremely tense party scene, a great deal of intrigue is derived from the way we only partially glimpse the comings and goings of the other family members from Josephine’s vantage point on stage, as she performs a hesitant duet of “Rolling on the River.”

CustodyThere are perhaps some moments where we might question a character’s behavior, though the “why doesn’t she call the police?” question is somewhat addressed by that opening scene in which we understand Miriam’s reluctance to involve the authorities further when they have refused to provide her with the protection she sought. Too often we judge victims of spousal abuse according to standards that simply cannot apply to someone psychologically scarred and vulnerable from years of domestic terror. For Miriam, it must be easy to assume that no one will come to her rescue, because for so long, evidently, no one did. Legrand’s skill is in making us feel the inescapability of that fear, and understand the inadequacy of a new address and the permeability of thin front doors when it comes to keeping someone out whom you once invited in.

Every year, in addition to a new crop of Oscar-tipped hits and established auteur works, the fall festival season features one or two titles that truly merit the term “discovery.” They come into their premiere with little buzz, but gather momentum as they move through the season, collecting silverware like a magnet picks up scrap iron. This year, that breakout position definitely and deservedly goes to Legrand and “Custody,” which won him Best Director in Venice, picked up the Best Film award in the Toronto Platform sidebar, and plays as part of San Sebastian’s appropriately named “Pearls” section. Because “Custody” isn’t just a fine film that makes vivid and visceral the escalating, suffocating all-pervasive terror of domestic abuse in a way few films have managed. It’s also an extremely auspicious debut for a writer-director with the rare, almost classicist ability to make utterly riveting drama out of painfully real life. [B+/A-]