McSteed, writing a book on Black Jamie, the 13th Laird of Castle De'Ath, and Emma, a member of Aborcashata (Advisory Bureau on Refurbishing Castles and Stately Homes as Tourist Attractions), arrive in Scotland at the invitation of a cousin of the 35th Laird. The vibrating brandy in Steed's glass at dinner and the implements of torture that Emma finds in the dungeons give them clues to the mysterious goings-on at Castle De'Ath.