Jessie Warner has married Tom Smith and their baby is almost due. Settling down into their new home in Bethnal Green, Jessie looks forward to her new life even though Tom is continually getting into mischief that borders on the downright criminal. Then the grim outside world intrudes when war begins and Tom is called up almost at once, leaving Jessie to cope alone when the air raids start over the East End. And when Tom does a runner and goes AWOL, things get rapidly worse. Meanwhile Jessie's clever twin Hannah has been recruited to help at Bletchley Park, cracking the Germans' communications code.