In 1944 Italian officer Captain Francesco Verdi is captured by Allied forces in North Africa and shipped to a POW camp in Michigan's Upper Peninsula, where the senior POW, the ruthless Kommandant Vogel, demands that all prisoners adhere to his Nazi dictates. His life threatened, Verdi escapes from the camp and meets up with an American woman, Chiara Frangiapani, who helps him elude capture as they flee to the Lower Peninsula. By 1956 they have become Frank and Claire Green, a young married couple building a new life in postwar Detroit. When INS agent James Giannopoulos tracks them down, Frank learns that Vogel is executing men like Frank for their wartime transgressions. As a series of brutal murders rivets Detroit, Frank is caught between American justice and Nazi vengeance.
Monsieur Perdu calls himself a literary apothecary. From his floating bookstore in a barge on the Seine, he prescribes novels for the hardships of life. Using his intuitive feel for the exact book a reader needs, Perdu mends broken hearts and souls. The only person he can't seem to heal through literature is himself; he's still haunted by heartbreak after his great love disappeared. She left him with only a letter, which he has never opened. After Perdu is finally tempted to read the letter, he hauls anchor and departs on a mission to the south of France, hoping to make peace with his loss and discover the end of the story.