White noise is the soundtrack for this grimly elegant urban fairy tale -- the rattle of a subway train, the whirr-hum of a washing machine, the gentle susurrus of a child's snores -- as if soft grumbling complaints were all the attention the world could spare its four child heroes, lost in the big city, utterly alone even while surrounded by millions of people. Twelve-year-old Akira (Yuya Yagira) wakes one morning in the cramped Tokyo apartment he shares with his mother (Japanese pop personality You) and three younger siblings to find that their only parent has left a handful of cash and absconded to who-knows-where, abandoning the children to their own devices. Determined not to let the little family fall into the hands of social services, and to keep the secret of the existence of his little brother (Hiei Kimura) and two little sisters (Ayu Kitaura and Momoko Shimizu) -- whom their mother, for inexplicable reasons of her own, kept hidden from landlords, schools, and indeed everyone else -- Akira takes over as head of the household. Writer/director Hirokazu Koreeda, inspired by real events, has created a deceptively simple story of devotion and survival, half-improvised and performed by an extraordinary cast of nonprofessionals, that is as surprisingly full of joy as it is of dread portents of disaster, as much a celebration of the discoveries of childhood and growing up as it is a tragic elegy to the forsaken and forgotten that exist literally before our very eyes in modern urban society.