Thundersley, Suffolk, 1942: A young man named Jim Walker shows up at Westleigh Farm, home of the Field family, demanding to be taught how to be a farmer but reluctant to reveal anything about himself.
When Thundersley Hall is bombed by a German spy, and Violet Field is taken into custody by the Ministry of War, it is up to her daughters, Patricia and Eleanor, to work out the connection between their new farmhand and the spy.
But suspicions in wartime run deep. Everyone seems to have a secret, even the Hall's owner, the aristocratic and handsome Alex Farrell. If his romantic intentions toward Patricia are sincere, why is he so unwilling to help her discover the truth about the bombing? And can Eleanor trust her growing fondness for the taciturn Jim, or is her affection for him because he reminds her so much of the brother she lost to the war?