In 1939 Maryland, eleven-year-old Frankie faces suspicion that her German-born father is a Nazi spy.

The narrow street where Harry Bernstein grew up, in a small English mill town, was identical to countless other streets in countless other working-class neighborhoods of the early 1900s, except for the "invisible wall" that ran down its center, dividing Jewish families on one side from Christian families on the other. On the eve of World War I, Harry's family struggles to make ends meet. His father earns little money at the Jewish tailoring shop and...