“Helicopters on their way from RAF Ruislip. Just hold out.”

“Not sure that’s going to be quick enough.” The building listed further. “I suggest you evacuate as much of the area as possible, at your end.” A little shake to his tone, but forgivable, he felt.

“Spiker,” Alison said, grabbing his shoulder.

“Wait,” he said, but the pinch of her fingers was painful. Is it colder, all of a sudden? Is she doing something again, or is it being done to her?

“Spiker,” she hissed. “Look.” Even as his breath plumed and floriate outscrollings of ice unravelled across the screen of his phone.

The sky had more depth to it than any sky had a right to display. On a clear day, he discovered, you really could see forever. And from the far side of forever something was approaching.

Then the first rat-soldiers spilled from the doorway, seemingly fighting each other as much as trying to apprehend the humans. The tower took that opportunity to sag again, and three of them just tumbled in a wrestling ball across the rooftop and were lost over the rail. Julian almost went too, saved by Alison’s grip.

The thing, the horrible thing on the other side of the sky, approached from infinitely far away, very quickly. It kept on approaching until he understood that it was far too big to be anything living. And yet it lived, and he felt they all must have shrunk down to the size of creatures that lived within a drop of water. Because abruptly it was here, in his sky, in his world, and it covered a score of postcodes with its shadow.

Julian wanted very badly to believe in God, right then. Not some C of E school lip service but a deep and comforting belief in which he could seek refuge.

Instead, he was forced to believe in a spined, segmented thing, kilometres long, hanging in the air as though physics had no more hold on it than reason. It had a head, or fore section, shaped like the crescent moon, and its shelled body was divided along its length into lobes. Protruding from the outer edges of each lobe were twenty-metre thorns which lined its flanks. Its underside bristled with limbs, some large enough to stamp on a double-decker bus, others so fine they could have adjusted a chess piece on a board. A woodlouse. A flying woodlouse the size of a village…

It was swinging in the air as though gaining purchase on some other, denser medium, skewing towards the tower top and its pitiful human–rodent refuse. Julian’s muscles fought for control of his bones, locking him rigid. He wanted to scream, but part of him—the part still answering to Julian Sabreur—refused.

Alison was looking up at the hideous thing in wonder. Ice danced in the air about her brow like a crown.