Aicha (Salha Nasraoui), her husband Brahim (Mohamed Grayaâ) and their young son Adam (Rayene Mechergui) live in a small coastal community in Northern Tunisia surrounded by dunes, sandwiched between the arid Sahara Desert and the Mediterranean sea. They inhabit a precarious shack and herd sheep. Their community isn’t particularly close-knit. They barely see their neighbours, and enjoy a mostly nondescript existence. Such ordinariness allows them to shelter their older son Mehdi (Malek Mechergui) and his pregnant wife Reem (Dea Liane), who have just returned from Syria. The gesture could land the entire family in jail. That’s because Mehdi and his brother Amine (who is now presumably dead) joined Isis of their own volition. The government sees them as terrorists, and a threat to national security.

The gruff, more pragmatic Brahim does not want Mehdi and Reem in the house. He describes joining Isis as “training in beheading and rape”, corroborating the views promoted by the Tunisian authorities. Aicha does not posses any strong political inclinations, instead allowing her motherly instincts to prevail. She wishes to protect her son, whatever the risks. Mehdi reveals that Amine was killed by Isis, but his mother refuses to believe him. She will do anything in order to vouch for the protection and the memory of her three children. Adam is a clever little boy whose confidence and chirpiness are dented by the sudden arrival of his brother and his new sister-in-law. He finds little comfort in the promise of soon becoming an uncle. He senses that there is something intrinsically wrong. And the consequences could be very serious, for the family and also the entire community.

Bilal (Adam Bessa, the award-winning protagonist of Lofty Nathan’s Harka, from two years ago) is an old friend of Mehdi, who seems to understand his decision to joins Isis. They talk about old acquaintances and the fate that befell each one of them. Many young local men have joined Isis, presumably enticed by the promise of a purpose in life, and in order to break away from an ordinary existence in poverty. Mehdi explains that he returned because Syria wasn’t quite what he expected, thereby highlighting the easy lure and the dangers of Islamic radicalisation. Bilal functions as both a sounding board and a peacemaker for the feuding family members.

Most of the suspense is constructed upon Reem’s character. She is covered by a purple niqab. Only her hands, adorned with a couple of golden bangles, and her sapphire-blue, bulging eyes remain visible. She never utters a word and never takes the garment off, not even in order to sleep. Mehdi demands that his mother never touches her, while also alleging that Reem is a Muslim who converted from Christianity after her entire family was killed by Isis. Adam is terrified of her. Viewers are left to guess whether she is a victim or in reality some sort of sinister villain. The colour of her garment (which is combined with the flowering desert shrubs in one of the film’s most stunning and enigmatic scenes) holds a clue: for Muslims, purple is the colour of spirituality, and it also an emblem against domestic violence (the International Purple Hijab Day is celebrated year in the second Saturday of February).

Who Do I Belong Too is a movie doused in mystery and beauty. The camera is often handheld and gently shaky, crafting a moderate sense of tension and uncertainty. The focus is very shallow, resulting in blurry, barely discernible silhouettes and dreamy landscapes in the background. The performances are quietly superb: Nasraoui excels as a mother overcome with anguish, while Grayaâ is a hard-headed yet sensitive father prepared to take hard decisions in order to vouch for his family security. The Mecherguis are two loving brothers tragically losing their fraternal connection, and the most vulnerable characters in the film (their thick eyebrows, heavily freckled faces and their common surname suggest that they are real-life siblings). But it is Liane’s astoundingly beautiful and expressive eyes who communicate the most. Her firm gaze evokes both fear and sympathy, while keeping the dark secrets of her soul securely hidden under the ruband. The developments are subtle and slow, however the film never overstays its relatively long duration of 120 minutes. A highly cryptic, jarring exuberant ending will stay with you for a long time.

Who Do I Belong To premiered in the Official Competition of the 74th Berlin International Film Festival, when this piece was originally written. Also showing in the Official Competition of the 2nd Mediterrane Film Festival (in Malta). The UK premiere takes place in October at the 68th BFI London Film Festival.