(Written and directed by Hiokazu Koreeda)

A childish-looking single mother moves into a new flat and introduces her 12-year-old son Akira to her new landlord. After a polite chat, mother and son go back to their own flat, where they open up two big suitcases. Out come two children: a boy and a girl, Akira's younger siblings, who are told to be very, very quiet, because if anyone finds out they're in the apartment, the family will be kicked out, like they have before. A few hours later, a fourth child shows up: 11-year-old Kyoko, who has waited in the street until it was dark before making her way to the new flat. She is informed that this is the last time she's been out; from now on, she has to stay inside to keep the little ones quiet while her mother is out working, so as not to alert the neighbours to the presence of the kids. Only Akira is allowed to go out; after all, someone has to do the family shopping.

The above would make plenty of material for a good film, but in "Nobody Knows", there's more to it. You see, it turns out that the mother has a habit of disappearing. Leaving the children some money, she vanishes for weeks on end, and when she comes back, she offers neither an apology nor an explanation for her absence. She just gives her kids some presents, explains patiently why they can't go to school like normal children, and tells them to bear their fate as well as they can. And then she disappears for good, never to return, leaving the kids to fend for themselves on a supply of money which is bound to run out very soon.

Loosely based on a true story which rocked Japan in the late 1980s, "Nobody Knows" is a tale of adult selfishness and children's resilience. It's the story of Akira, a boy forced to become a father of three at an age when most kids only think of playing games and skiving off school. Akira makes a brilliant surrogate father to his siblings. He finds them food, buys them chocolates when they're feeling low and keeps up morale by telling them their mother will soon return, even if he is by no means sure of this himself. He even gives them presents ostensibly sent by their mother, so that they won't hate her for abandoning them for such a long time. But he's only twelve years old, and like most 12-year-olds, he has more on his mind than just being a sweet older brother.

More than a just a harrowing family drama, "Nobody Knows" is a coming-of-age drama, which in Akira gets an appealing hero: a 12-year-old who knows the well-being of his younger siblings depends on him, but also wants to be a normal teenager who hangs out with friends, plays video games, tries to be cool and dreams of becoming a baseball star. The problem is that Akira doesn't actually have any friends, because he doesn't go to school and is too busy scoring food for his siblings to hang out and do the things kids his age do. But he really wants to be a normal teenager, he really does, and in the discrepancy between his dreams and his actual circumstances lies half of the drama.

"Nobody Knows" is a marvellously directed film. It was shot chronologically over the course of a year, and it shows. Not only do the children get dirtier and more obviously neglected as the film progresses, but they actually visibly grow older. It is obvious Koreeda established an atmosphere of great trust with his young cast, because the scenes shot in the tiny Tokyo apartment where seventy per cent of the action takes place ooze naturalness. Even the smaller children, one of whom was apparently quite hard to instruct, come across as completely natural. In doing so, they infuse the incredible story with some recognisability. We all know children like the ones depicted in the film; they may lead extraordinary lives, but at the end of the day they're ordinary kids, who react to their bizarre circumstances the way every child would. In showing us these children in a fly-on-the-wall manner, Koreeda not only tells an amazing story of juvenile resilience, but effectively presents us with a chronicle of childhood in general. It never gets sentimental or truly shocking, but with its quiet, documentary-like approach, it packs an emotional punch rarely seen in Western cinema.

There is some superb acting in the film. Yuya Yagira was awarded the top acting prize at Cannes for his incredibly realistic depiction of Akira, and rightly so; he does a brilliant job capturing the boy trapped between childhood and adulthood, between responsibility and escapism. Ayu Kitaura is equally good as his frustrated 11-year-old sister Kyoko, who dreams of becoming a pianist but only has a toy piano to practise on. Hiei Kimura and Momoko Shimizu are cute as hell as the younger children, and TV personality You (who actually functioned as a kind of second director on the set) is so cringe-inducingly irresponsible and selfish as the mother that you regularly want to smack her to beat some sense into her. It's actually a relief when she buggers off for good, because as hard as life may be for the children without a loving parent, you get the feeling they're better off without her, because she is such an unwholesome presence in their lives.

"Nobody Knows" is a near-perfect drama. If it has any flaws, they're in its length (at 141 minutes, it feels a tad long; the second act could have done with some judicious editing) and in the fact that the kids are just a little too cute and well-behaved to be completely realistic. Don't get me wrong, they're perfectly natural, and often completely adorable, but even so, you sometimes wish for an equally natural tantrum or crying fit to get the whole spectrum of children's behaviour. These are minor flaws, though; what remains is a powerful, masterful film that stays with you for a long time.

Elaine