It is 1939 and working-class Evie Bishop has received a scholarship to study mathematics at Oxford when tragedy turns her life upside down. She must seek a new future for herself; inspired to contribute to the war effort, she 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 - shy, awkward May and flirty, glamorous Jess. Faced with earning the approval of strict officers and finding their way in a male-dominated world, the three girls band together to overcome challenges, navigate new romances and keep their pilots safe in the skies. 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...