During World War II, eleven-year-old Felicity is sent from London to Bottlebay, Maine, to live with her grandmother, aunt, uncle, and a reclusive boy who helps her decode mysterious letters that contain the truth about her missing parents.

During World War II, Felicity Bathburn is living in Bottlebay, Maine, with her eccentric relatives and their foster child Derek, whom she has grown to love, but when a man claiming to be Derek's true father arrives and starts asking all sorts of strange questions Felicity becomes suspicious of his motives.