In which the detective White Mason arrives to investigate a most perplexing and unusual murder at a venerable English Manor House, and together with Holmes and Inspector MacDonald, they scrutinise the perplexing scene—marked by an odd weapon, mysterious footprints, and a strange card—as well as the baffling circumstances surrounding the deceased's death. With the village stirred and suspicions mounting, the explorers of this dark enigma piece together tentative theories but find themselves confronted by contradictions and a most elusive assailant.