Because he suffered from insomnia the Rev. Peter Bordesley was the first person to turn in the alarm that Lughorse Cottage was a mass of flames, and he happened to be on hand when the local police found the body of a man in the smouldering ruins. The good parson also noticed an oak stake, with mistletoe wound around it, and, knowing his Norse mythology, was able to interpret the whole peculiar business as a modern enactment of the Balder legend. When Scotland Yard was called in and discovered that the murdered man had been James Henry Fenchurch of the Defense Ministry, whose death and possible treachery became a matter of national importance, the Rev. Bordesley was able to point the way for the whole investigation.

Inspector Arnold of the Yard and his amateur assistant, Desmond Merrion, were among the many who were frantically trying to find out whether, before he died, Fenchurch had divulged the air defense plans with which he had been trusted. A platinum cat, broken from a pin, was found among the ruins of Lughorse Cottage, and Merrion later was to find the pin from which the cat had been broken. The other actors in the Balder legend were located, but international agents are hard to control with extradition papers, and it was only when Merrion, tracing an old photograph, found the personal motives behind the murder....