Paul, a 10-year-old east London estate kid, prepares his mum's breakfast... takes the spoon, cooks the heroin, charges the syringe and carries it all in to her on a tray. Her "medicine", he innocently calls it. The child's ignorance - "What's a junkie?" he has to ask - about the role that drugs play in the ailing, acned, depressed and wasting life of his widowed mum (Molly Parker) is the only implausibility in a performance that is the main reason for seeing Gillies MacKinnon's new film.