We critics spend so much time carping about crappy films that it takes a bit of an adjustment when something comes along that just plain works.

Monsieur Lazhar is one such film: a cinematic story that is so effective, it seems almost effortless.

To reveal the inner workings of why Philippe Falardeau's movie succeeds would be like unwrapping someone else's gift. Instead, I'll try to entice you by describing a scene near the beginning.

In a busy Montreal school, a young boy ends recess early to help distribute cartons of milk. When he reaches the door of his classroom, he sees something horrible. We watch the boy run off down the hallway, presumably to alert his teachers.

As the camera remains trained on the empty hallway, we wait and hear the sound of kids coming back into the school. The clamour gets louder until, at the last moment, a teacher rushes in and ushers them away from the classroom door.

Stripping the scene down to its bare essentials, Falardeau increases the tension while at the same time never showing us what the teachers are trying to spare the children from seeing: the body of their teacher, who has hung herself in the classroom.

Monsieur Lazhar is a movie about grief, guilt and mourning. The students and their late teacher are linked. Stepping into the scene, with the smell of fresh paint still in the air, is Monsieur Lazhar: a substitute teacher from Algeria who carries his own personal baggage.

Fellag, an Algerian comedian and humourist, takes a serious turn in Monsieur Lazhar. (Vro Boncompagni/eOne films)

This is a quiet film, filled with gentle moments. That's not to say this is a movie without weight, but this drama does have a way of sneaking up on you. The natural performances Falardeau draws out of his actors could be part of its power. Working with children can be tricky, but Monsieur Lahzar manages to capture the key window when young people are struggling to define themselves and take responsibility for their actions.

With their absent parents and busy schedules, it sometimes seems the young students are left on their own. It's up to them and this strange and stuffy substitute teacher to carve a path through the bureaucrats and make peace with the past.

Luckily for the class, and for the audience, we have Mohamed Fellag as Lazhar. He's an odd fit in this bustling city school -- a teacher who dictates from Balzac and wears his single, threadbare sports jacket as a suit of armour. Fellag gives us a man who is thoughtful and persistent.

Like the children, his Monsieur Lazhar is in transition. In the end, with empathy and affection, they help each other.

Rating: 4.5 out of 5

Monsieur Lazhar is open in select theatres across Canada.