Ok, the basic plot.
Natalie Portman is a ballet dancer in the chorus line of a ballet company who is given the opportunity to dance the part(s) of the Swan Queen in Swan Lake. For those not in the know, this means she has a dual role of the pure and innocent White Swan who must find true love to break the spell of having been transformed into a swan, and also the sexy sinister Black Swan, who seduces her true love away from her, leaving her with no dramatic option but to commit suicide at the end. As far as I can tell, the Prince in this story is falling in love with two swans, actually being seduced by one of them. Which leads me to say "careful now, that swan could break your arm" in a slightly uncomfortable voice. I don't understand ballet.
Anyway, this girl is under tremendous pressure. She's got an overbearing, suffocating ex-ballet dancer mother (Barbara Hershey), determined to live out through her daughter the career that she had to give up to have her daughter. Hence, at the age of, let's say, "nearly thirty", Natalie is still sleeping in a pink-decorated soft-toy-infested bedroom, and has probably never had sex or sufficient minute to minute privacy from her mum to even see to her own needs in that area.
She's also got, in Vincent Cassel, an overbearing, slightly pervy (slightly? maybe more than slightly) ballet director who insists that she gets in touch with her heretofore untapped and untrammelled sexy side in order to play the Black Swan properly (the White Swan, she has down pat already.) There's also a rival dancer in Mila Kunis, who's ready to take the role over if she can't do it.
So, with all this pressure, after pretty much a lifetime of similar pressures, it's not too surprising that she begins to crack up, hallucinate and generally start to self-harm and fall apart. And that's your movie.
There is much to like in this movie. The direction is pretty masterful, really; Darren Aronofsky does a very good job of slowly altering the style of the piece, from the start in the hyperrealistic gritty style he shot The Wrestler in, towards the end, where it's a Lynchian nightmare of "everything in this shot is completely normal, and at the same time, completely weird and wrong." So that's brilliant. Vincent Cassel is great, there's a weirdness behind his eyes which is never quite reflected in his actions, and for me it's the performance of the movie. However, nobody starts a paragraph "There is much to like in this movie" unless they have some serious reservations.
Here's my problem. Here is a video clip of Natalie Portman in this movie:
Oh, wait, no it's not. It's a still jpeg. But it may as well be a video clip, because that's the expression she has frozen on her face the whole damn movie. I would be willing to believe that's the expression she's had on her face since the end of Revenge Of The Sith. She certainly had it for the vast majority of V for Vendetta. She's got one "Natalie Portman Is In Anguish" face, and it doesn't shift an millimetre for the whole movie.
I am told that she's been nominated for an Oscar for this performance, and I'm told that she's heavily tipped to win. Well, I personally cannot imagine why, and looking at the list of nominations right now, if she does win, I shall personally be outraged on behalf of Annette Bening (The Kids Are Alright) and Jennifer Lawrence (Winter's Bone) who were so much better than this, that it's not even funny.
So, it's bizarre, in that it's an incredibly well shot and put together film, with excellent support, centred around a performance that really isn't worth anyone's time at all in my view. Your mileage may vary, as the mileage of many other people evidently has, given all the fuss and palaver.