That is the behavior of a man who plans, who studies the movements of a household the way a burglar studies a street, who understands that his power depends entirely on isolation and arranges for it deliberately.

I had felt, for two years, that Arthur’s menace was somehow spontaneous — an old man’s clumsy inappropriateness, as David kept insisting.

Standing in that doorway I understood it had never been clumsy at all.

It had been meticulous.

Every “accidental” hallway contact had been chosen.

Every kitchen visit had been timed to when I was alone.

And this confrontation, tonight, had been waited for — held in reserve until the exact hour the house could not protect me.

It is a strange thing to feel, the recognition that the danger you’re facing is not impulsive but designed, that the man in your doorway has been quietly running the numbers on your vulnerability for longer than you knew you were a target.