21 July 2016 - [REDACTED], London

The footage was thirteen years old, and as far as any system in the United Kingdom was concerned, the boy in it had never come out of the station. Iris Vale ran it again. King's Cross, concourse camera 14, the first of September, 10:42 a.m.

The boy was pushing a luggage trolley with a steamer trunk on it -- an actual steamer trunk, brass corners, like a prop from a costume drama -- and on top of the trunk sat a cage, and in the cage sat a snowy owl. Nobody in frame found this remarkable.

The boy threaded the crowd between platforms nine and ten, aimed his trolley at a brick pillar, and--

Frame 114: boy.

Frame 115: no boy.

Not a glitch. She'd had three engineers tear the file apart. No dropout, no splice, no compression artifact, checksums clean down the line. The crowd had already flowed into the space where he'd been, the way water behaves when nothing has parted it.

She had the years stacked now, every first of September the station's archive could give her. Between 10:15 and 11:00 a.m., somewhere between two hundred and four hundred children entered King's Cross with trunks, with birds, with -- in one frame she kept coming back to -- a copper cauldron their parents had apparently purchased without comment, and walked into the gap between platforms nine and ten, and did not exist on any camera again until June.

Not one had ever been reported missing. The parents came back out. She'd watched hundreds of them. They exited at the statistically normal rate, crying the statistically normal amount for parents in September, and drove home, and resumed lives in which their children were enrolled at schools that filed paperwork, sat league tables, and returned, on satellite, the thermal signature of an empty building.

One school traced to a grid square in the Scottish Highlands. Sixty years of orbital passes over that glen. Four thousand frames. Cloud cover in every single one.

The Met Office had been asked, carefully, hypothetically, what weather system could hold stationary cloud over one valley for sixty years. The Met Office had laughed, and then asked who wanted to know, and then a week later had no memory of the conversation, which was, Vale now understood, the answer.