On an ordinary day in 1941, a letter arrives on the doormats of five young women, which will change everything. Lillian is distraught. She must register for compulsory war work. Many miles away, Emily is also furious to leave her dream job as a chef, whilst Alice must abandon her plans of college. Meanwhile, Elsie feels a kindling of hope at the possibility of leaving her brutal father. And down in London, Agnes has her own reasons to smile. Brought together at a munitions factory in a Lancashire mill town, the five new bomb girls will find friendship and strength that they never before thought possible.