The key is long and still warm, and the yard outside is going grey. Pike has said he will search at first light, and he searches the way the order tells him to.
Hour Four: where it will keep

Pike has said what he will search, because the order tells him: every chest, every bed, every press and cupboard, every hearth and chimney, and every board that lifts. He says it through the shutter in a sing-song, the way a man says a thing he has said at a great many doors.
Phoebe takes you by the sleeve to the foot of the great stair. Her grandfather had it made, she says, by a joiner from Hertford who was proud of himself, and the joiner's bill is still in the steward's closet because her grandfather never paid all of it. Tobias has it out already:
THE GREAT STAIR, 1612 treads, oak 14 balusters 28 the handrail 1 the string 2 the newel 1
And the joiner carved something round the post at the foot of the stair, which Phoebe says she has been reading since she could read:
I STAND AT THE FOOT I HOLD UP THE RAIL MY HEAD COMES OFF AND I AM EMPTY
Tell Phoebe where the key goes.
Tobias says the joiner's bill names every piece of that stair, if you want them named.