Deep in the heart of Swansea, Wales, lives a small girl with some big secrets to keep. Secrets that make her one of the best actresses on the planet - because no-one would ever think that, away from school, Audrey is the sole carer for her increasingly sick mam and her two younger siblings - or a seasoned thief. With her worlds threatened by the arrival of a mysterious, invisible neighbour, behind whose closed curtains and shut front door may lie a spy, Audrey must take matters into her own hands to save her family. Inspired by her beloved collection of stamps, her friendly neighbourhood postman (and fellow stamp collector), and her two best friends, off Audrey must go: on an adventure that will lead her to places - and hearts - she never knew existed.