She thought of it later, as she lay in her bed, listening to light rain. He had readied and recovered himself like a monk, fought like a machine, and seemed to feel it like a predatory beast. That tension frightened her, much more than the combat skills he had shown. Those could be learned.

Bellis helped Shekel through books that grew more complex by the hour. When they separated she left him exploring the children’s section again, and went back to the rooms where Silas waited for her.

They drank tea and talked about New Crobuzon. He seemed sadder, quieter than usual. She asked him why, and he would only shake his head. There was something tentative about him. For the first time since meeting him, Bellis felt something like pity or concern for him. He wanted to tell or ask her something, and she waited.

She told him what Johannes had said to her. She showed him the naturalist’s books and explained how she was trying to piece together Armada’s secret from those volumes, without ever knowing which were important, or what within them might be clues.

At half-past eleven, after an extended silence, Silas turned to her. "Why did you leave New Crobuzon, Bellis?" he asked.

She opened her mouth, and all her usual evasions came to her throat, but she remained silent.

"You love New Crobuzon," he continued. "Or… is that the best way to put it? You need New Crobuzon. You can’t let it go, so it doesn’t make sense. Why would you leave?"

Bellis sighed, but the question did not go away.

"When were you last in New Crobuzon?" she said.

"More than two years ago," he calculated. "Why?"

"Did word reach you, when you were in The Gengris… Did you ever hear of the Midsummer Nightmare? The Dream Curse? Sleeping Sickness? Nocturne Syndrome?"

He was flicking his hand vaguely, trying to catch the memory. "I heard something from a merchant, a few months back…"

"It was about six months ago," she said. "Tathis, Sinn… Summer. Something happened. Something went wrong with… with the nights." She shook her head vaguely. Silas was listening without scepticism. "I still have no idea what it was-it’s important you know that.

"Two things happened. Nightmares. That was the first thing. People were having nightmares. And I mean everybody was having nightmares. It was as if we’d all… breathed bad air, or something."

The words were inadequate. She remembered the exhaustion and the misery, the weeks of dreading sleep. The dreams that woke her screaming and weeping hysterically.

"The other thing. There was a… a disease, or something. People were being afflicted all over the place. All races. It did something… It killed the mind, so there was nothing left but the body. People would be found in the morning, in the streets or in bed or whatever, alive, but… mindless."

"And the two were linked?"