An ingenious murderer caught out by a persevering policeman. A small cast of varied suspects, with an "impossible" murder. A lot of insight into the mind of the detective -- about the murder, and about other things. An engaging personality. Set in the an English village (in Loamshire) during the World War II blackout. This is the second of the author's books about this detective, Guy Northeast. She apparently abandoned him as being "too nice", and her later books featured a more objectionable detective.