When the Nazis march toward Paris, American ballerina Lucie Girard buys her favorite English-language bookstore to allow the Jewish owners to escape. The Germans make it difficult for her to keep Green Leaf Books afloat. And she must keep the store open if she is to continue aiding the resistance by passing secret messages between the pages of her books.

Widower Paul Aubrey wants nothing more than to return to the States with his little girl, but the US Army convinces him to keep his factory running and obtain military information from his German customers. As the war rages on, Paul offers his own resistance by sabotaging his product and hiding British airmen in his factory. But in order to carry out his mission, he must appear to support the occupation—which does not win him any sympathy when he meets Lucie in the bookstore.

In a world turned upside down, will love or duty prevail?