Unconstrained by notions of balance, non-fiction cinema has done a more complete job of describing the devastation wrought by the Syrian conflict than swathes of the broadcast and print media. Sean McAllister’s A Syrian Love Story plotted the ups and downs of a couple forced into European exile; Matthew Heineman’s City of Ghosts starkly laid out the agonies of citizen journalists trying to break the story internationally.

Those films achieved their power through an awareness of distance, whether between director and subject or subject and homeland. Framed as a mother’s letter to her young daughter and opening with footage of an airstrike as experienced from inside the target zone, the exceptional For Sama drops us into the thick of things from the start.

The film resembles a home video from a bomb site. Waad al-Kateab took up the camera in 2012 to document the protests of her fellow students against President Assad. She kept filming as Aleppo fell under siege, turning from the carnage only to record her growing affection for a doctor, Hamza, and the birth of their first child, Sama.

Unignorable … For Sama.

These vignettes, now stitched together with the British film-maker Edward Watts, comprise the most compelling screen study yet of how this conflict blitzed everyday life. The new mother struggles to put the youngster to bed as terrifyingly loud shells explode; she notes the insecurity that comes from seeing friends shot down and your neighbourhood pummelled into craters. Sama derives from the Arabic for sky, yet here the name becomes synonymous with hope, a promise of better times to be protected at any cost.

That risks making For Sama sound more sentimental than its predecessors, yet the scared, often scarred children passing before the lens would indicate that Syria is no place for sentimentality. Even the sleepy-eyed Sama seems to be living on borrowed time. “Lots of airstrikes today,” mum tells baby, in one striking normalisation of conflict, “but they didn’t hit us. Yay!”

Sifting six years’ worth of rubble, al-Kateab turns up beauty and one earthly miracle to set alongside the horrors, but horrors there are. If the extremes involved preclude easy viewing, it remains profoundly moving and unignorable, whether as proof of Assad’s barbarism, or the unfailing ability of this world – and its most engaged cinema – to break your heart and sear your soul.

• For Sama is released in the UK on 13 September.