Two men have been enlisted to kill the head of the Gestapo. This is Operation Anthropoid, Prague, 1942: two parachutists are sent on a mission by London to assassinate Reinhard Heydrich, chief of the Nazi secret services. His boss is Heinrich Himmler but everyone in the SS says 'Himmler's brain is called Heydrich', which in German spells HHhH.
