In WWII strange lights, later called 'Foo Fighters' were reported by Allies. But what exactly were these strange lights in the sky? Was it the German V2 Rocket, or something even more sinister...? Also in this episode; We hear the true story behind the secret British SS and the famous aristocrat who tried to court Hitler, the amazing story of a US dentist and his secret plan to release killer bats on Japan, and the Polish mass grave that is still unexplained to this day.