Above Suspicion — Helen MacInnes

“A red rose, a chance phrase, and some spilt cointreau--this was the first link in a chain of events that were to lead Richard and Frances Myles to Nazi-dominated Germany. The young Oxford don and his attactive wife were sent by the British Foreign Office to find out if a certain man was still alive--a man on whose life a delicate web of rescue work and espionage hangs precariously. The Myleses were chosen because they were above suspicion. There innocence was their strongest card. They could slip by where secret agents feared to tread . . .”