Mallory arrives at a remote Scottish Highland hotel seeking peace after traumatic experiences abroad. While there, he overhears fragments of a secret island-language code being spoken by some guests , he hears the code again in a hushed conversation. Later, young Seraphina, a refugee child, is found murdered, seemingly silenced for knowing too much.

Author Charity Blackstock is one of the pen names of Ursula Torday (1912–1997), a British novelist known for gothic romance and mysteries.