German Jews in England at the outbreak of WWII were interned in camps, until one bright British general decided that many of these Germans (the Jewish ones) might want to fight for England AGAINST their own country's Nazis. Manfred Gans, celebrated American chemist fights with other members of this elite "X-Troop" then finds his own parents in a concentration camp. Here’s an interview with Manfred Gans:
“One Less Fight - The Story of Manfred Gans”