Oh, wow, this was amazing. I absolutely love the music imagery, especially "If he were a musical interval, he'd be an augmented seventh, Watson thinks, almost the bell tones of an octave but not quite, a little more ethereal, a little more wild." And the whole paragraph where Watson puts it all together. Trans!Holmes - so much love.

And even despite not having read the books in a long time, you really managed to capture the way that they speak in them. :)