🚲 Violet Hunter
The governess who consults Holmes about a job that pays too well and requires her to cut her hair. Observant, steady, and brave enough to explore a locked wing on instruction — the canon's best client-turned-operative.
“I confess that it is not the situation which I should like to see a sister of mine apply for.”
The client who read the danger herself
Violet Hunter comes to Baker Street not with a mystery but with a job offer that smells wrong: a salary far above market, cheerful employers, and odd conditions — cut her hair short, wear a particular blue dress, sit where she is told. She has already reasoned her way to suspicion; what she wants from Holmes is a second opinion and a lifeline. He gives her both, and the telegram she eventually sends — 'Please be at the Black Swan Hotel at Winchester at midday to-morrow' — is among the canon's crispest calls to action.
An operative in all but name
Inside Copper Beeches, Miss Hunter does what no other client dares: she observes systematically, tests hypotheses (the mirror-shard trick to see who stands behind her), and searches the locked wing on Holmes's instruction. Holmes pays her the canon's rarest compliment — that she is a quite exceptional woman, whose observations would have earned her a place in his profession.
The mystery she was hired to be
The solution — she was recruited as an unwitting double for an imprisoned daughter, her silhouette in a window staged to wave a persistent suitor away — makes her both detective and clue: the case is about what her own appearance was being used to say. Watson notes with mild disappointment that Holmes lost interest in her once the problem was solved; the canon gives her the better ending anyway, running a school in Walsall.