On a frozen January evening in 1944, Nancy Levin and her three-year-old daughter, Emily, flee their East London home as an air raid siren sounds. Not far away, Diana Meadows and her own three-year-old daughter, Abigail, are lost in the blackout as the air raid begins.
They hurry to the safety of the underground tube station, but in wartime people will do anything to survive—even at the expense of others.