Chapter 17: Portrait Intelligence

The Headmistress's office was dark when Holmes arrived.

Not entirely dark — the castle was never entirely dark, having apparently decided that perpetual ambient illumination was a structural requirement on a par with load-bearing walls. The instruments on the shelves emitted their steady miniature weathers. A brass device near the window rotated with a sound like a sleeping breath. The portraits on the walls held their familiar dim shapes, the painted occupants apparently retired for the night in whatever sense a painting retired — some had vacated their frames entirely, leaving empty chairs and abandoned desks, and one particularly stout medieval gentleman was simply asleep in his, chin on his painted chest, emitting what might technically have been a snore.

Holmes stood in the doorway for a moment, cataloguing the room in its nocturnal configuration. He had been in this office four times. He knew exactly which floorboards registered weight in the section between the door and the central desk, and he stepped over the relevant two now out of habit, though there was no particular reason for silence. McGonagall was not here. The castle was doing what the castle did after midnight, which involved a great deal of settling and murmuring and the occasional sharp crack from a beam somewhere overhead, all of which Holmes had concluded was structural theatricality rather than genuine distress.