London's skies are burning. But two young women are ready to fight back. In 1941 London, World War II is far from over. Identical twins Maggie and Tillie have each suffered loss and heartbreak, but their hardships are only just beginning. With Maggie's beloved Micah far away in German-occupied France, and Tillie's fiancé Trevor fighting on the front line, the girls need each other now more than ever. Which is why, when Maggie is confronted with a choice, it is one of the hardest she will ever have to make: stay with her sister and family or leave them behind for a dangerous role in the Women's Army, manning the anti-aircraft batteries protecting London's skies. However much it pains her to leave, Maggie can't ignore her duty. And besides, fighting on the front line makes her feel just a little closer to Micah. But life as a war girl puts Maggie's bravery and resolve to the test every single day. Will Micah get out of France in time? Will Trevor return safely from the front line? And will Maggie and Tillie beat the odds and survive when the sky above them is ablaze in war?