Penina Zeitchik was just 3 years old when the Nazis approached the little town of Lubieszow, where she lived with her family. The town had been part of Poland before World War II, but in 1939, it was occupied by the Soviet Union under the Molotov–Ribbentrop Pact, in which Germany and the USSR had secretly carved Poland between them. Once home to some 1,500 Jews, during the Soviet occupation, the Jewish community swelled, with refugees fleeing the Nazi reign of terror. But in 1941, Adolf Hitler tore up his agreement with Josef Stalin, and, within weeks, the Nazis were on...