Documentary filmmaker Waad al-Kateab is in the Syrian city of Aleppo when its citizens begin a civil uprising that leads to a five-year siege on the city by Russian and Syrian military forces. Through helping to establish a makeshift hospital, to finding love, facing tragedy, and giving birth to a daughter named Sama, she continues recording with her camera for five years.

For Sama is a remarkable document of terrible historic events. Its footage is immediate and powerful, and emotively narrated throughout by al-Kateab in the form of a spoken letter to her daughter. It is easily one of the most powerful and affecting documentaries that I have ever seen. Individuals are introduced, and later die. It does not hit the same emotional beats with which moviegoers are accustomed, because these are not characters in a narrative – they are real people who died in dreadful circumstances. Through the camera lens we see people with terrible wounds and deep trauma. We see people die. We see children struck down from horrifying injuries. This is a profoundly difficult watch, but the human cost on display demands that we do.

It is the structure of the film that makes it work more than any specific moment of footage – which is generally hand-held, rather shaky, and shot on videotape. It has been edited together superbly, in a manner that illuminates its protagonists’ lives and the geography of their Aleppo suburb. There is something deeply haunting about the way that the city’s buildings degenerate and collapse over the course of the film. It also mixes the bigger picture of Aleppo’s gradual devastation with al-Kateab’s pregancy and the birth of her daughter: destruction and creation jostling against one another giving the whole documentary a deep soaking in humanity. There is a surprising seam of humour running through the piece. It comes from real families living in the most absurdly dangerous conditions. Al-Kateab co-directs with British filmmaker Edward Watts, but it feels overwhelmingly to be her movie using her own footage and personal life to give events a grounding and a perspective.

The documentary largely refuses to engage with the politics of the Syrian Civil War, and does not address directly any actions or potential crimes by rebel forces in Aleppo. This is not necessarily a bad thing; al-Kateab keeps her focus on her husband’s work operating the hospital, and on the military bombardment of civilians with missiles, cluster bombs, and even chemical weapons. Any way you tell the story, it is one of a dreadful injustice against human beings and an important document of a government massacring its own people.

While it is important to watch, the film is difficult to sell. The footage is horrifying. It showcases real injuries and trauma, and confronts the viewer with actual death. There is a sequence in the middle of the film where a badly injured woman is brought into the makeshift hospital. She is heavily pregnant and has gone into labour. When her child is born – a limp, motionless and grey thing – al-Kateab’s camera lingers on a doctor’s frantic attempts to bring it back to life. It is one of the most distressing things I have ever seen on screen, but I am thankful she was there to capture it. I am thankful to everyone involved in bringing Aleppo’s story to the screen, because these things are important. These lives matter. This is documentary at its most urgent and powerful. I cannot promise that this film will not upset or disturb you, but I can urge you to hold fast and watch it.