Snow Flake is a tale of insulated lives thrown into contact, of insights that that are almost (but not quite) incommunicable, of the power of unusual friendships, of people defying what is expected of them and sometimes of what they would expect of themselves, and of finding a strength in themselves and others as a result. And if that sounds clichéd, you have to go and see it to believe it.

Sigourney Weaver is from a different world, one not unlike our own. She's not battling Aliens or living in a sectarian time-shift Village, but the world into which she brings us is as weird, and dazzling enough for my jaw to drop after watching her for just a few minutes. Her presence jumps off the screen with such vividness that, even though I had read the storyline, I knew it was going to surpass my expectations. Her character is fascinated by things that sparkle, can juggle numbers with unnerving rapidity, inhabits a universe of extreme precision that brooks no infraction, and no uncleanliness: and she's only barely tolerant of your world. This is the world of Linda Freeman, high-functioning autistic.

There are two sides to Linda: the world she lives in is undoubtedly extraordinary - her version of Scrabble leaves Alan Rickman's character (Alex Hughes) looking severely unevolved - but it is balanced by her lack of empathy for 'normal' people. What makes Weaver's performance so remarkable is that she conveys the logical certitude of Linda's position with such force that we, like Alex, start feeling a bit dumb. Why do we go through such irrelevant tea-and-ham-sandwiches rituals after a death? Why can't we feel the joy we felt as children when we discovered snow in our hands, or the thrill of a trampoline as our body is launched into space? Why do we struggle to remember simple facts? The drawbacks of Linda's world (apart from most people not being able to reach it) is that she cannot cope with the imperfections that the rest of us would shrug off. If the dog leaves a stain on her carpet she will have simply have to 'move house', and the only kind of job she can get is one where her obsessive need for order can find a simplistic outlet (she stacks shelves in a supermarket, with mathematical precision and attention). If Rain Man was the gold-medallist of autism, Linda Freeman is simply a non-glamorised regular sportswoman, and in that she conveys a more real person than any Hollywood-ised super-character.

Alex (Alan Rickman) opens the film, flicking poignantly at a small photo as he sits out a long flight. We have no clue as to who the person in the picture is, or why he seems to be encased in his own intense thoughts. Later, we see him in a transport café, approached by a bubbly young girl who is determined to break down his wall of silence. She wants to write a book and make loads of money - by finding the right areas of pain and suffering to focus on. Her apparent insensitivity is quickly tempered when she admits she admits she needs a lift but has picked the loneliest looking person because she really thinks he "needs to talk". Alex reluctantly gives her a lift. She is soon singing the 70's rock song All Right Now at the top of her voice, but things are far from all right. One car crash and an added truckload of emotional baggage later, Alex is arriving on Linda's doorstep and destined to be her guest for more than a few hours. Our storyline is further complicated by the seductively attractive Maggie (Carrie-Ann Moss) who has her eye on Alex. He first assumes she is a prostitute (she reminded me of the classy call-girl Inara, from Serenity) but accepts a 'neighbourly' invitation for dinner.

Rickman is at his best. The wry tongue-in-cheek humour seen in many of his films gives way to a sardonic realism that is even funnier because it is more true to real life. A very down to earth script ensures the laughs are grounded (Love Actually but without the unbelievability),even if in most cases Rickman is principally a foil for other characters: such as when Linda likens eating snow to an orgasm or Maggie breaks off dinner because she hates having sex on a full stomach.

We soon realise that Linda's childlike behaviour thinly disguises a penetrating intelligence, but her intelligence doesn't enable her to solve everyday problems such as putting the rubbish out. She has emotional insight, even consideration, but her world is as isolated from ours as ours is from hers, even with her ability to reel off facts and figures. One is reminded of a recent study that suggested that emotional intelligence may serve people better in the workplace than a Mensa certificate.

Rickman's character struggles with Canadian distances in a typically British manner. "It didn't look far on the map," he exclaims hopelessly. He is out of his depth geographically and emotionally but, obsessed with his own inadequacies, is open to seeing things differently. The landscape whiteness, at first cold and unwelcoming, starts to seem beautiful. Maggie allows Alex to open emotionally whereas Linda, through the intellectual effort he makes to reach her, enables him to rationalise the process and come to terms with his feelings. Linda is a doorway to seeing things differently - "I'm half outside, half inside," she says as she hovers on the porch and we puzzle whether she is being dippy or intentionally defusing a difficult situation. The mathematical way she describes needing a hug reassures us that she is human, but by then we have learnt a whole new attitude of respect. Snow Cake is a very personal film, not a blockbuster, but a few more films like this could enrich the way we see ourselves.

If you think this is one of those dull and oh-so-PC movies about autistic people, think again! Nothing could be further from the reality. 'Snow Cake', much to my surprise and delight, turned out to be an exhilarating, sexy, poignant, movie that was full of love, redemption, and healing. And no, don't worry, the sex wasn't with the autistic character! I had heard about this movie the other day on BBC Radio 4, when Sigourney Weaver was interviewed on 'Women's Hour', I think it was. Whatever the radio show--- even that interview made it sound a bit 'well meaning' and earnest. And that makes for one dull-ass movie! Therefore, while the interview raised my desire from zero to maybe 35 percent, I still was hesitant to go and see it.

I wish I had proper words to describe what a masterpiece this is. And it was a masterpiece, perhaps, because it was NOT obviously 'arty' or 'important'. It was about people. Real people. Wounded people. Alan Rickman delivered what is perhaps the best role of his career. Sigourney Weaver's performance as the lady with autism was so seamless that if I didn't know better, I'd think she WAS autistic. And the young woman who played the daughter, Emily Hamspshire I think her name is--- she was a refreshing dose of realism. We should watch for her as a rising new star. And Carrie-Anne Moss was fantastic as the sex interest.

This movie is simple and straightforward. Yet, nothing was predictable, either. I just loved it. This is exactly the kind of movie treasure that movie lovers usually can only dream of finding. And to think, I only saw it 'accidentally', because I had already seen everything else at the cinema.

I am SO glad I went! The movie, I promise, is NOT about autism, or how we treat sufferers, or any other boring PC diatribe. It is about ME. And YOU. It's about all of us, and our hearts, and the inspiration and healing and good luck that we all yearn for, and we all deserve. Now, after this movie, the picture of what is possible is bigger, clearer, and stronger for me. Now THAT is a gift to me! Thank you, cast and makers of 'Snow Cake'!

This film is just a beautiful story that made me laugh and cry. Sigourney was just fantastic, have never seen her better. I was so lucky to meet her in Edinburgh where she did a 'reel life' interview about her career. Sigourney described how in depth she studied the role and was nervous about not being able to do it, which took her out of her comfort zone. All I would like to say is all the hard work was worth it. The scene where Linda dances at the wake just got my heart, I felt I was transported into Linda's world and you cannot ask more from a film.

It was so good to see a film without ego, cgi or violence, just a gentle take on extreme circumstances. Please please please go see this film and even if it is just to find out what 'DAZLIOUS' means!