Izzie hasn't been to Swallowcliffe Hall since she was small, but after a bout of tuberculosis, she's sent to stay with her Grandmother Polly, who is still a housekeeper there. While at Swallowcliffe she meets Andreas, a German refugee who has been taken in by the local shopkeeper. It doesn't seem as if he's being well treated, so Izzie helps him to get work at the Hall. But as the threat of a war with Germany grows, people are suspicious of Andreas, and when a fire breaks out in Lord Vye's attic studio, nearly killing one of his daughters and Izzie's grandmother, the finger is pointed at the German interloper. Can Izzie prove his innocence?