Before the action starts in French-Canadian writer/director Xavier Donan’s 5th movie, we are told we are in a Canada where, as of the 2015, new legislation means parents of unruly children are allowed to dump their kids into any hospital for the state to take charge of – effectively ending their legal responsibility to their offspring.

Once we’ve been told this of course, it doesn’t take much imagination to work out that this will be a key feature of upcoming events. It’s almost a shame that we needed this explainer at the beginning. That these details couldn’t come out through the storytelling, as they predicate the inevitable route the story will take, is unfortunate.

Diane (Anne Dorval) – an independent, argumentative but decent single mother collects her utterly obnoxious son Steve (Antoine Olivier Pilon) from a juvenile correctional institution after he burns down the school canteen, severely injuring another pupil.

The film is structured around Steve and Diane’s relationship, and also with their quiet neighbour Kyla (Suzanne Clément) – a woman who has a psychological linguistic block and finds it difficult to get words out and communicate.

Steve, we discover, has ADHD and is on medication. This clearly explains his impatience, lack of social skills and tendency to show extreme emotion. And irrational behaviour. He is inappropriate, racist, boorish, violent, and self-obsessed. He is to put it mildly “a handful.”

Steve, Diane and Lyra flourish together. Lyra volunteers to look after Steve and teach him, and it’s here we find him at his calmest and most grounded. Diane is calm and happy, and Lyra finds spending time with them allows her to speak with no hindrance.

Unusually the film is shot (mostly) in a 1:1 aspect ratio – a perfect square which is kept in tight on the characters. It also goes some way to highlighting how imprisoned they are by their circumstances; getting on with things in a small, confined arena. Dolan has said (in an interview included with the Extras) “I didn’t want to strand my characters in their own misery, bathed in grey light and pouting in defeat.”

Rather than using broad and elegant screen pictures to tell the story, he relies on the performers who are closely focused in upon.

There are two moments in the film where the screen picture stretches to full 16:9 – and both of these feel fully earned by the events which precede them – it is a curiously effective cinematic trick. Suddenly the situations and the characters are given space to breathe – to literally stretch out and feel free.

As mentioned, this kind of tight cropping relies on the performances to shine from the enclosed box, and that they do. The performances are uniformly excellent. Dolan has a close working relationship with Clément and Dorval and despite his relative youth has written two very well rounded older characters for these excellent actresses to play. He has spoken of his desire to create strong, significant, anti-stereotyped roles for actresses and has achieved just that. Steve is very well acted by Pilon, but is a problematic character in that being so dislikeable any supposed charm he has is negligible to say the least. Oddly the film flies when the character isn’t on screen. You feel empathetic towards his situation, but sympathy for the character is harder to win.

Much, much harder.

Dolan has built a clever audience/ character relationship because of this. The second moment the picture broadens to full screen is the moment we understand everything.

It’s something of a cinematic coup and will spoil things to mention what happens here – but it is revelatory and explains all-encompassing familial hope and love in a single montage. The whole film appears to be built around that single moment of understanding.

It is ultimately a very simple story about motherly and almost Oedipal love. It is simply told, with winning dialogue and performances at the centre. But the 1:1 aspect ratio takes a long time to get used to, and as mentioned the character of Steve is a very tough one to like. By the end of the film you do understand him, but he makes it a necessarily rough ride.

As a movie it’s by no means perfect, but has a very great deal going for it.