Tucked into the rugged Canadian wilderness of Muskoka's majestic lake country, Merilee Sutcliffe's peaceful town seems worlds away from the escalating conflict in Europe. But life is about to change dramatically in the Summer of 1940. As her patriotic friends and relatives leave for battle, her small town is thrust into the war machine. Merilee's formerly tranquil skies soon roar with aircraft from the Royal Norwegian Air Force, stationed nearby to train young men determined to liberate their country from Nazi occupation. When German Prisoners of War march into her shocked community, they become Merilee's closest neighbours - and biggest threat.

What unfolds in her remote town and on foreign shores sets Merilee and her growing circle on a collision course with an unimagined destiny. Caught up in the chaos is Luftwaffe pilot Erich Leitner. Shot down during the Battle of Britain and transplanted to a lakeside prison in Muskoka, he discovers he has more to fear from his comrades than his captors.

While her cousin-in-spirit, Elyse Thornton, navigates the treacherous skies of Britain as a Spitfire Girl, audaciously ferrying warplanes from factories to airfields, Merilee becomes quietly entangled in her own dangerous liaisons on the home front. Caught between worlds, with conflicted loyalties and a sense of duty, she joins the Royal Canadian Air Force, Women's Division, and soon finds herself in ground-zero London, focusing her photographer's lens on a city under bombardment.

Far from carefree summers on the lake, struggling to survive the relentless demands and sacrifices of war, Merilee, Elyse, and their friends wonder if they dare to risk their hearts as well.

As unlikely lives intersect, ideologies and social hierarchies are challenged, loves and friendships are forged or broken, and countless heroes are made and lost. But even those who return to the serenity of Muskoka are changed forever.