The urchin who tackles the mighty is a staple of folklore, the fantasy that just occasionally finds a place in news stories. Trash is a fable, based on a young adult novel by Andy Mulligan. For the screen it has become an international collaboration of film-making, social awareness and community activism; it is also entertaining. The action takes place in contemporary Rio de Janeiro. Two kids scavenge on a rubbish tip, sifting what little of value they can from the city’s detritus. One day, one of them finds a wallet, which is intriguing not so much for its cash than for photographs, tickets and other assorted clues. The wallet has been thrown on to a garbage truck by a man embroiled in political and criminal corruption. Maybe he is a protagonist, maybe he is a whistle-blower. Soon