A light snow is falling. A runner in gloves and hooded black tracksuit goes pounding away from us along the curving paths of Central Park, New York. Enchanting music – flute, a triangle, strings – quivers in the scene’s icy air. At the entrance to a dark underpass the runner hesitates, stumbles, and drops to his elbows and knees. He grovels, his back hunched. A heart attack? The music tells us that he’s dying, right in front of us, in the mouth of the tunnel.

Cut to a meaty, blurred close-up of a naked infant, glistening in the fluids of its birth. Next, under the words Ten years later, a lone woman in a snowy cemetery turns and walks away from a headstone.

This extended set-up grows gratifyingly in texture and complexity. It appears that Anna, the childless young widow (Nicole Kidman), has been alone for ten grief-stricken years since her husband Sean died that winter day in the park. But her determined solitude has finally buckled under the attentions of a dogged suitor, Joseph (Danny Huston), and now we see them at their engagement party, in her family’s vast, museum-like Upper East Side apartment.

It’s meant to be a celebration, but there’s strain in the grand rooms. It might just be my personal anxiety about Kidman’s wig, a little brown coconut-cut like Mia Farrow’s real hair in Rosemary’s Baby; or a sense that Joseph is the wrong guy for her, and also kind of scary; or the unexpected arrival of two friends from the past who don’t seem to like her much. But things don’t get seriously weird at this party – and we don’t grasp what the newborn baby signifies – until a ten-year-old boy (Cameron Bright), also called Sean, slips past the servant at the door and announces to Anna, with solemn urgency, that he is her late husband. He has come to stop her from marrying Joseph and to reclaim her for himself.

Nobody believes him, of course, least of all Anna. They turf the kid out, but he keeps coming back. He is privy to facts about her intimate life with the first Sean that no one else could possibly know. Bit by bit Anna’s scepticism crumbles before the child’s certainty. She allows him further into her life. They discuss their situation. She enters into, and encourages, his fantasy that they have a future. They even take a bath together. Kidman sits in the water, watching young Sean strip off his boyish clothes. His little white belly, above his cotton underpants, is chubby and dimpled with childishness. This scene is supposed to have “ignited controversy” but it’s comically unsexual, almost endearingly innocent.

Anna’s fiance, meanwhile, is crazed with jealousy and rage. Her family think she’s losing her mind – and maybe she is. Is she permanently deranged with grief? What is this child? Is he a manifestation of her secret doubts about her coming marriage? Or is this a metaphysical thriller? What sort of story are we being told here?

Its basic conceit would seem more ludicrous if the movie – directed by Jonathan Glazer, who made Sexy Beast, and shot by Harris Savides – were not so wonderful to look at. It has a gorgeous, parchmenty quality that makes the mouth water. It teems with ideas for the eye. Everything it does, visually, tempts us to go on trusting it past the point where we might otherwise have said, “No, really, this is just too silly.”

Glazer sets up shadowy tableaux, like paintings, of people in large splendid rooms, staring in angry suspicion at young Sean, who faces them with a pained gravity, insisting on his identity. The camera is always panning through doors in the immense apartment to fix on a character standing alone, absorbed in troubled reverie. Shots of restless, surging street crowds in dark coats, or of pale ranked faces at the opera, are as ominous and as thrilling as Bill Henson photos. The film’s sombre aesthetic, its strange mood of muffled incredulity, can almost seduce us into feeling we’re on the territory of Henry James’s great tale of possession, The Turn of the Screw.

But two things are wrong. One is Kidman herself. When such a blatantly manufactured force as the Nicole Phenomenon keeps coming at you every time you open your front door, it is a point of honour to put up resistance. I long for her to wriggle out through the bars of her stardom, to persuade me she’s not made of cardboard. But I can’t get past that thin, nasal little voice with its high-school intonations; those melodramatic brows; the awful girly thing that happens when she laughs.

The second thing that betrays Birth is the way the story resolves. All I’ll say here (since it’s worth seeing for its visual richness, and its clever use of music) is that a woman turns up with a cache of love letters. At that moment the whole premise of the movie blows up in our faces. A director like Almodovar might have bounded past this problem in an exhilarating way, and sent us back into the day-lit world with our hearts rinsed clean by wonder and laughter. Glazer, though, simply dumps into the mix a load of realism that flattens out his phantasmagoria and strips it of the magic he’s so delicately created.

He tries to rescue it with another of his splendid visual flourishes – a final, silent scene where Kidman in her wedding gown wades weeping into a cold surf and is dragged back to shore by her new husband. Stiff-armed in long cream gloves, head back and howling like a diva, she is led away into what we can only imagine will be a wretched second marriage. Oh, it’s a handsome scene, and superbly shot, but it’s too late, the spell is broken; and we stump out of the cinema feeling once again disenchanted, melancholy and ill-used.