Oxford, 1942. Frederick Rowlands receives an urgent summons to the university city from his old friend - also a blinded war veteran - Major Ian Fraser. They are to meet Professor Duncan Challoner, Fellow of Brasenose College, now working with MI5 at nearby Blenheim Palace. Challoner is about to divulge the identity of an enemy agent at Blenheim - but is murdered before he can do so. Also taking an...