One of the deepest differences between life in the city and life in the country is that in the former, you can choose your own family, and in the latter, it is given to you. The peculiar mystery at the core of Hirokazu Kore-eda's beautiful and deceptively tranquil masterpiece Shoplifters will never be properly solved if one does not have this understanding in mind. The urban family is composed of strangers, and the poorer the city dweller is, the more dependent he/she is on this kind of informal union.

The family in Shoplifters lives in a small home in some forgotten quarter of Tokyo. The father is unable to work because of an accident at a construction site. The mother was laid off from a crummy job at a factory. The mother's sister works in the sex industry. The children shoplift to make ends meet. The family's only sure source of income is the grandmother's pension transferred to her from her dead husband. (The grandmother also has a taste for gambling.) One day, the family adopts a stranger—a girl from an abusive home. She is a runaway. She joins the family and soon also learns the art of shoplifting.

Much of the film is spent in their crowded little house. Clothes and useless goods are heaped on the floor, the bathroom is dirty, the kitchen is too tiny. The family eats a lot of ramen. But this life of poverty has its pleasures. The table conversations are lively. The house has a small garden. There is a trip to the beach. The boy thief has a growing crush on the girl thief. The parents have steamy sex during a rainstorm.

But something is wrong with this family. It is, it seems, too united. Most families, be they poor or not, aren't so harmonious. Despite the constant failures to secure incomes in the brutal job market and the constant need for money and the threat of gentrification, this Tokyo family is really tight. The mystery of their unusual unity is not exposed until the film's last 30 minutes.

There is a good reason why Shoplifters won the Palme d'Or at this year's Cannes Film Festival. It is a carefully and beautifully crafted work that appears to be about one thing (the strong bonds of family life), but is really about something else—the way a city forces us to invent our lives.