Molly lives with her repugnant father, who has betrayed her many times. From a young age, living on the streets of London’s East End, she has seen the harsh realities of life . . . When she’s kidnapped by a gang and forced into their underworld, her future seems bleak.

Flo spent her early years in an orphanage, and is about to turn her hand to teacher training. When a kindly teacher at her school approaches her about a job at Bletchley Park, it could be everything she never knew she wanted.

Will the girls' friendship be enough to weather the hard times ahead?