It's April 1944, England is preparing to take the war back into Europe, and the girls of the Air Transport Auxiliary Mystery Club become mixed up in a desperate fight to save a dear friend from forces who would threaten the very existence of the country. The girls find solace in their deep friendship, even though the presence of a Nazi spy ring threatens their essential war work and their very lives. Can love blossom through a fortunate meeting, and will they survive a period where life seems determined to put them in mortal danger? The girls find the strength to battle through all the war throws at them, whilst still keeping a stiff upper lip, a witty repartee, and unbreakable spirit.