London, 1938. Hanna and Jack Foster had been sent to an orphanage when their parents were killed in a train crash, but were separated when a couple adopted Jack. Bullied and treated like a slave, it soon became clear it was a dreadful mistake. In desperation, Jack takes his future into his own hands and runs away to join the merchant navy, while Hanna takes a job looking after two children. For a time, life seems good, but war is looming and threatens to take away everything Hanna holds dear . . .