It is 1939, and working-class Evie Bishop has received a scholarship to study mathematics at Oxford when tragedy turns her life upside down. Evie must seek a new future for herself and, inspired to contribute to the war effort, joins the Women’s Auxiliary Air Force as an Ops Room plotter. Posted to a fighter station on the Sussex Coast, Evie befriends two other WAAFs. But the German bombers seem to know more than they should about the base’s operations, and soon Evie, May and Jess are caught up in a world more dangerous than they ever imagined. 

Lady Joanna Harcourt and her daughter, Sarah, discover their life of luxury at Goodwill House is over. Because with Lord Harcourt away fighting, the Harcourt girls are facing financial ruin. Lady Joanna is terrified of losing their home, but for Sarah, this means her dreams of becoming a doctor are over. Headstrong Sarah isn’t one to quit! War or not, she’s determined to find a way to save her home and follow her dreams - whatever it takes.

Pearl has given up on her dreams of being a journalist after being denied a promotion because of her gender. Joining the WAAF as a radio telephone operator for Bomber Command, Pearl's new job at RAF Fenthorpe serves two purposes – providing an income for her grandmother, and keeping a close eye on her younger sister, Thea, an instrument repairer at another Lincolnshire bomber station.

When duty calls, East End girl Minnie Wolton isn’t afraid to do her bit. She’s excited to be joining the ATS girls and although she knows life at the barracks will be tough, she’s not one to quit! She just hopes the other girls are all good sorts. With her husband away fighting, Eileen Ruffel is glad of the break from her unhappy marriage. She just wants to make a success of the ATS girls and maybe find happiness too. Along with the other girls, Minnie and Eileen strike up a firm friendship. The training is hard, but they are determined to prove they are the best new recruits.

Claire has always had a special bond with her aunt Margaret, but she’s astonished when Margaret suddenly begins talking about a friend called Agnes, who Margaret met working as a WAAF in World War 2 – a past Claire had no idea about. Margaret and Agnes were best friends until Agnes started acting strangely, becoming secretive and distant. Then one morning, Agnes vanished and never returned home, leaving Margaret distraught. Claire promises to delve back into the past and help discover what happened to Agnes.