One day, while Holmes and Watson are having a conversation in the Baker Street flat, a young woman comes calling. Miss Mary Sutherland is a relatively well-to-do woman who works as a typist. She is, Watson says, “a large woman with a heavy fur boa round her neck, and a large curling red feather in a broad-brimmed hat which was tilted in a coquettish Duchess of Devonshire fashion over her ear” (51). She lives with her mother and the mother’s much younger second husband. Mary’s fiancé disappeared on their wedding day and the young woman seems the only one concerned with the situation. Both her mother and stepfather want her to forget about the incident. However, she is unable to do so and comes to Holmes as a last resort.

Mary met her beloved, Hosmer Angel, at a ball. They always meet at dusk, and he wears dark glasses and speaks in a whisper. He also types all of his correspondence, including the signature. Holmes immediately deduces that the missing lover is in fact Mary’s stepfather. As long as the young woman lives with her parents, they have access to her significant inheritance. However, she wants to have a family of her own.