Roberta likes to collect the letters she finds in second-hand books. When her father gives her some of her grandmother's belongings, she finds a letter from the grandfather she never knew - dated after he supposedly died in the war. Dorothy is unhappily married to Albert, who is away at war. When a plane crashes in the field behind her house she meets Squadron Leader Jan Pietrykowski, and as their bond deepens she dares to hope she might find happiness. But fate has other plans for them both, and soon she is hiding a secret so momentous that its shockwaves will touch her granddaughter many years later.