A resourceful 12-year-old, who secretly lives alone in her flat in a working-class suburb of London, makes money stealing bikes with her best friend Ali and keeps the social workers off her back by pretending to live with an uncle. But when her estranged father turns up out of the blue, she's forced to confront reality.

From war-torn Syria to the 2016 Rio Olympics, two young sisters embark on a risky voyage, putting their hearts and their swimming skills to heroic use.