Murder of a Lady

Duchlan Castle is a gloomy, forbidding place in the Scottish Highlands. There, late one night, Mary Gregor is found murdered in her own bed. She has been stabbed to death - but the room is locked from within, and the windows are bolted. The only clue as to the culprit is a tiny silver fish's scale, left on the floor next to Mary's body. Superstitious locals mutter of half-man, half-fish creatures from the local waters. Inspector Dundas is dispatched to Duchlan to investigate the case. Luckily for him, amateur sleuth Dr. Eustace Hailey is also on the scene...