Shot in the depths of winter, Jean-François Lesage’s black and white documentary finds the warmth hidden beneath the snowy streets of Montreal. A melancholic jazz score weaves in and out of this enchanting film, which luxuriates in the profundity of unexpected encounters between strangers and the delicate cycle of things lost and regained.

Peering through the glass shield of a lost and found counter, the camera patiently observes the flow of people searching for objects they have left behind on public transport. From paper folders to handbags, these articles of everyday life gain a new poignancy through their disappearance. Some of the items are treasured for more than utility, with sentimental value playing its part.

Moving beyond the glass barrier, the film comes face-to-face with the owners of these missing objects, opening up its scope to a world of intimate revelation. A woman’s happiness at having retrieving her wallet gives way to a touching memory about a difficult childhood with her parents, whose picture sits neatly among her credit cards. Gradually, the various tales of loss extend beyond material possessions: people talk of broken relationships, loved ones who have died and families that are left behind.

Without giving too much away, the film’s most transcendental moment occurs towards the end, when these anecdotal threads are cleverly knitted into a musical piece that transforms individual losses into a symphony of collectivity. Losing something – or someone – is a destabilising experience, yet it also brings people together in this beautiful mess we call life.

• Prayer For a Lost Mitten is available on 26 August on True Story.