There were four, to begin with: spirited, striking daughters born to an unhappily married Tunisian mother, Olfa Hamrouni, who claims that she “hates girls” (although in fairness, she has even less goodwill for the males of the species). Of the four, the two youngest, Eya and Tayssir, remain at home with their mother. The two older girls, Rahma and Ghofrane, were radicalised as teenagers and left their family to join Islamic State in Libya, making headlines around the world. The circumstances leading up to the girls’ drift towards fundamentalism are explored in this inventive and compelling documentary by Tunisian director Kaouther Ben Hania (Oscar-nominated for this film and her previous one, The Man Who Sold His Skin).

It’s a tricky, sinuous work – a hybrid of sorts, blending the reminiscences of the mother and the two remaining girls (all three are engrossing natural storytellers) with dramatic reconstructions. Ben Hania cast actors Nour Karoui and Ichraq Matar to play Rahma and Ghofrane respectively, and the celebrated Egyptian-Tunisian star Hend Sabri steps in as Olfa, ostensibly to take over when the scenes are too painful for the real Olfa, but also to interrogate her, unpick her motivations and to challenge her version of the story.

The story is already filtered through a cracked lens, distorted by generations of emotional and physical violence, meaning that Olfa has never been the easiest mother. It’s also a situation twisted by the rigid patriarchal structures of conservative Tunisia, which seem ready to condemn young women for almost anything, but most of all for the crime of beauty. Olfa looks with fear at her vivid, laughing, dark-eyed girls and rages at them, for moral weaknesses concocted in her paranoid imagination. This is an emotionally wrenching film that takes its subjects to bruising places and is not above mining them for dramatic impact. But it’s also full of love, optimism and defiant humour.