On the night of August 3, 1944—in the hot crickety darkness of Riga, Latvia—my grandparents did two remarkable things. After midnight, while his children were sleeping, my grandfather—Harijs Mindenbergs—sat down at the kitchen table and wrote three letters: One to Benita, his wife. One to Juris, his son. And one to Ruta, his daughter and my mother. Soviet troops were advancing toward the city. In five hours, most of the family would flee to Germany.