For as casually as we often toss around the word "hero," sometimes no lesser term applies. Tonight we'll introduce you to members of a secret American intelligence unit who fought in World War II. What's most extraordinary about this group: many of them were German-born Jews who fled their homeland, came to America, and then joined the U.S. Army. Their mission: to use their knowledge of the German language and culture to return to Europe and fight Nazism. The Ritchie Boys, as they were known, trained in espionage and frontline interrogation. And incredibly, they were responsible for most of...