 While Holmes is indulging in recreational morphine, he vacations with Watson at the estate of his old school chum Ralph Musgrave. Musgrave s butler is discovered prying into an enigmatic, centuries-old family document outlining an apparently meaningless ritual. When the butler and a maid he was romantically involved with disappear, Holmes and Watson set about deciphering the ritual s meaning which they hope will lead them to a long-buried treasure.