Snow Cake is the Canadian version of the American Beautiful Mind, which fed off the success of Shine, the film that launched Geoffrey Rush into star territory. It is quite lovely, though.

I wept frequently. Autistic Linda Freeman's (Sigourney Weaver) daughter Vivienne (Emily Hampshire) is killed in Alex Hughes' (Alan Rickman) car after he gives her a lift. Because she is autistic, Linda's responses are not ordinary. It is refreshing and it is meant to be. The movie thus runs commentary on conventional behaviour in a way I have not seen for a while. In literature, the precursor would be Camus' The Stranger.

Alex' being English adds a touch of the exotic to the scene, a small Canadian town where everybody knows everybody. But it is the character of Maggie (Carrie-Ann Moss), a stunning and promiscuous dark-haired liberal, that makes the movie sing. In addition to 'adopting' Alex and bedding him, she keeps in touch with the plodding cop Clyde (James Allodi), whose impotent suspicions provide benign background noise that serves to highlight the eccenticity of the situation without causing anxiety.

This is not Mad Max. When finally Dirk and Ellen Freeman (David Fox and Jane Eastwood) arrive to mourn the death of their granddaughter, there is no need for them to legitimise an otherwise odd menage-a-trois. Even the dog, a scruffy animal fed bananas and cake icing, injects pathos and humour into the movie by throwing up on the carpet (which sends Linda into paroxysms of grief the death of her daughter didn't elicit).

Weaver is stunning. And Rickman's low-key attentions give a solid profile to her eccentric compulsions. And while the filmmakers make light of them we are never led to either fear or deride her. Although this is the third in an eloquent series, I do think that the more of this type of film that gets made, the better.