Everyone tells Sophie that she was orphaned in a shipwreck, but she is convinced that her mother also survived. When no one will believe her, she sets out to prove them wrong. On the run from the authorities, Sophie finds Matteo - a boy who walks tightropes and lives in the sky. With the help of her loving guardian, Charles, who has taught her never to ignore a 'possible', they set out on a race across the rooftops of Paris. Will they be able to find her mother, before it's too late?