It is 1937 and Spanish Civil War veteran Stephen Sefton is stony broke. So when he sees a mysterious advertisement for a job where "intelligence is essential", he applies. Thus begins Sefton's association with the eccentric Professor Swanton Morley, an omnivorous intellect. Morley plans to write a series of guides to the counties of England and, together with Morley's daughter, Miriam, they begin their tour in Norfolk. But when the vicar of Blakeney is found hanging from his church's bellrope, they find themselves drawn into a rather more fiendish plot. Did the Reverend really take his own life, or was it murder?