Holmes, retired to Sussex, is drawn into a last case when his arch enemy Moriarty arranges with an American gang to kill one John Douglas, a country gentleman with a mysterious past. Holmes' methods baffle Watson and Lestrade, but his results astonish them. In a long flashback, the victim's wife tells the story of the sinister Vermissa Valley.
Will Hay, back in his role as a hapless teacher, is hired by a grim school in remotest Scotland. The school soon starts to be haunted by a legendary ghost, whose spectral bagpipes signal the death of one of the staff. Hay, assisted by Claude Hulbert and Charles Hawtrey, has to unravel the mystery before he becomes the next victim.
Unsuccessful writer Aylmer Franklyn takes the chance to change identities after he discovers a corpse. However, he soon finds himself accused of the murder of a maid at a near-by boarding house.
A man tells his wife that the police are after him for having killed a bookie during an alcoholic binge, but that he is innocent and is being framed for the murder. The wife and her brother hide him and try to find out who the real killer was. The more they investigate, the more holes they begin to find in the husband's story.
