In 1942, Boston teenager Jessica Stanfield is learning about life and its complexities in a time of war as she sees her German housekeeper Anna harassed and threatened. Her parents, anxious for Jessica's safety as well as Anna's, send them to spend the summer in one of the dune shacks of the backshore of Cape Cod.

Jessica is enchanted by her new independence as well as by the wild nature that she discovers in the dunes. She is befriended by a local girl, Sophie, the daughter of a fisherman, and as time passes the girls' special friendship deepens. But the summer isn't just idyllic: rumors of camps in Europe, the presence of U-boats off the coast, and dangers even closer to home put Jessica's newfound strength to the test. And when she's called upon to make decisions about what is right and what is wrong, she finds that she has to grow up... quickly.

This coming-of-age novel enriches readers with its descriptions of Provincetown and the Outer Cape during WWII, but also challenges their assumptions and underlines the moral ambiguity present in any age during wartime.