here is a moment in this almost forensically severe film when a furious mother jams her fingernails into her rebellious daughter’s cheek. Her hand is transformed for a second into a claw, and the girl’s face clenches into a grimace, not resisting the imminent assault. But after a moment, her mum thinks better of it, removes her hand and storms away, perhaps humiliated by having descended to her daughter’s level of childish spite without even being able to go through with the threat. Not a drop of blood has been spilled, yet it is the most authentic moment of violence imaginable. This debut feature by the Iranian-Canadian director Sadaf Foroughi takes what might otherwise be a banal family-drama trope – moody teenage girl with warring parents starts acting out – and turns it into something resembling a political thriller. In present-day Iran, and many other strict societies, a teenage girl who presumes to challenge her parents and teachers is made to feel like a dissident in a police state, forever nursing secrets, forever being questioned and harassed by the authorities, forever getting her friends into trouble as possible accomplices and losing those friends as they decide where their own loyalties lie. Foroughi’s camera sometimes seems like a surveillance device, recording the scenes from fixed positions which sometimes cut off heads and doesn’t show one of the characters in one dialogue scene. The result is not unlike a movie by Iranian film-maker Asghar Farhadi – who has himself imbibed the icier techniques of the European arthouse – and sometimes like a play by Terence Rattigan. Ava, played with pressure-cooker resentment by Mahour Jabbari, is a teenage girl in Iran who is beginning to lose her temper with her parents, with school and with life itself. Her mother, Bahar (Bahar Noohian), is a hospital doctor, stressed and overworked, with a need to control and discipline her increasingly intractable daughter. Her easygoing husband, Vahid (Vahid Aghapoor), is often away on business, so the heavy lifting of parenthood is up to Bahar. She is beginning to dislike Ava’s music lessons, which she now thinks are not just valueless academically but involve Ava mixing with unsuitable female friends and also possible secret boyfriends. Meanwhile, Ava has bet her obnoxious, sneery classmate Shirin (Sarah Alimardani) that she can’t go on a date – something heartbreakingly platonic and innocent – with a boy called Nima (Houman Hoursan) so she needs her friend Melody (Shayesteh Sajadi) to cover up for her. Bahar becomes so hysterically suspicious and angry that she makes a garden-variety teen escapade into something much worse and takes Ava to a gynaecologist to make sure that she is still a virgin, an act of cruelty that leads to a shocking incident. Ava is being similarly bullied and intimidated by a fastidious headteacher who wears a pair of white gloves with which she daintily picks sugar cubes out of a hygienically wrapped jar for her tea. This film immerses you into its world so pitilessly that it isn’t until it is over that you realise that its pettinesses, misogynies and micro-tyrannies are outrageously pointless. You are so swept up in Ava’s terrible situation that it almost doesn’t occur to you to note that every problem here is the creation of the heavy-handed political class of the parent/teacher world. Ava herself is used to moving around the family apartment as noiselessly as a cat, eavesdropping on her parents, who are astonished to learn that Ava knows something shaming about their early life together. How does she know? Probably through hearing them discuss it, because they are often so dysfunctionally indifferent to her existence as a young adult. What is even more disquieting is that music itself – that precious educational and cultural commodity – is ambiguous here. Is music an escape or just another refinement of torture? Ava has a sharp-tongued and rude music teacher, a classic proponent of “high standards” who makes music into an ordeal, and perhaps that is the point: Ava’s violin lessons were acceptable to her parents because they were a time-consuming ordeal of tension and subjection. Ava is made with superb technique and real style.