On vacation from London on the beautiful Italian coast, 28-year-old Elena Standish and her older sister Margot have finally been able to move on from the lasting trauma of the Great War, in which the newly married Margot lost her husband and the sisters their beloved brother. Touring with her camera in hand, Elena has found new inspiration in the striking Italian landscape, and she's met an equally striking man named Ian. When Ian has to leave unexpectedly, Elena, usually the more practical of the sisters, finds she's not ready to part from him, and the two share a spontaneous train trip home to England. But a shocking sequence of events disrupts their itinerary, forcing Elena to personally deliver a message to Berlin on Ian's behalf, one which could change the fate of Europe. Back home, Elena's diplomat father and her secretive grandfatheronce head of MI6, unbeknownst to the familyare involved in their own international machinations. Worried when Elena still hasn't returned from Italy, her grandfather starts to connect the dots between her change in plans and an incident in Berlin, where Adolf Hitler and the Third Reich are on the rise. It seems the message Elena delivered has forced her into a dangerous predicament, and her grandfather's old contacts from MI6 may be the only people who can get her out aliveif Elena can tell the difference between her allies and her enemies.