It's summer 1938, and for the second time, Britain is threatened by war with Germany. This time civilians too will be in the front line. In London, two very different families are brought together by the war. Doctors, Amy and Dan, have twins, eighteen year old Tessa and Charlie. Nora, a working-class wife and mother, has a twelve-year-old daughter, Sara whose dream is to become a doctor, a wild idea for a working-class child. Together, and helping each other, the two families struggle to survive and endure the six years of war, and Sara fights to reach her impossible dream.