Guernsey, 1940. As war storms through Europe, Churchill orders the evacuation of all military personnel from the island. Boats ferry soldiers and vulnerable young children to England, leaving their parents and loved ones behind to face the invading German army on their own. One of the few remaining policemen on the island, Jack must protect not only his friends and family, but also the woman he loves: Johanna, a Jewish nurse from Germany, whose secret faith could prove fatal to them both.
While George has always been the brother to rush towards the action, fast becoming a boy-soldier when war breaks out, Joe thinks differently. Refusing to fight, Joe stays behind as a conscientious objector battling against the propaganda. On the western front, George soon discovers that war is not the great adventure he was led to believe. Surrounded by mud, blood and horror, his mind-set begins to shift as he questions everything he was once sure of.