I was twelve that summer, visiting my aunt and uncle for a week. Their home was ancient, a sprawling structure from a different time, with floors that groaned under every step. I was given a small room at the end of the upstairs hall.
Directly across from my door was an odd architectural feature. A large, interior window, set high in the wall, connected the hallway to a sunroom that had been added on decades later. It had no pane, just an open square of darkness looking into another part of the house.
I woke suddenly in the deep of the night. The blanket had slipped to the floor. My room was utterly dark, but a faint, greyish light from a distant streetlamp touched the hallway outside my open door.
As I lay there, too awake to sleep, I stared into the hall. My eyes were drawn to that empty window. For a long time, there was only the silence of the old house. Then, a shape moved within the sunroom beyond the opening. It was not a person, but a slow, deliberate shifting of the darkness itself, a patch of deeper night that uncurled and seemed to press against the frame of the window, looking out.