During WW2 there was a rumour that German spies were landing by parachute in Britain, dressed as nuns... Conradin Muller was an unusual spy. He was recruited in Hamburg in June 1943, much against his will, and sent on his first, and only, mission in late September that year.

He failed to send a single report back to Germany, and when the War came to an end in May 1945, he fell to his knees and wept with relief. From a highly reluctant German spy who is drawn to an East Anglian nunnery as his only means of escape, to the strange tale of one of the Cambridge spy ring's...