One day, she unexpectedly receives a fan letter from an American college student named David Graham. David loves Elspeth's poetry and what starts with a simple fan letter quickly turns into a dedicated correspondence from both sides. Elspeth and David only have their letters, but in it they share everything with one another, from their darkest secrets to their dreams and goals. When World War 1 takes over their lives, and David becomes an ambulance driver at the front, everything could change in a second. In 1940, at the start of another war, Margaret Dunn finds an old letter from a man called David, and she is determined to find out what happened to her mother all those years ago.