Purloined Letter
The best way to hide something is in plain sight.
19. The little brown-haired girl bouncing up and down in front of them was an affront to his senses, Sherlock decided. He was never very good with children, especially ones that clearly showed no intelligence in their heads and would grow up to be some kind of addle-pated shop assistant selling laundromats or something equally invaluable. "Hello, Sherlock," John said, holding onto her hand. "This is my daughter, Molly."
...What?
(Number 20 is for you, my beautiful insomniac, as it always is, resting amongst the clouds of sound.)