“The Cacotopic Stain I know, of course. That is always what one hears when the Torque is discussed. Perhaps it is a bogeyman.” Isaac could not distinguish moods in Yagharek’s voice, but his words were defensive. “Perhaps we should overcome our fear. And Suroch…I have read your histories, Grimnebulin. War is always…a vile time…”

As Yagharek spoke, Isaac stood and walked to his chaotic bookshelves, flicking through the stacked volumes. He returned with a slim, hardbacked folio book. He opened it in front of Yagharek.

“This,” he said heavily, “is a collection of heliotypes taken nearly a hundred years ago. It was these helios, in large part, that put a stop to Torque experiments in New Crobuzon.”

Yagharek reached out slowly and turned the pages. He did not speak.

“This was supposed to be a secret research mission, to see the effects of the war a hundred years on,” continued Isaac. “Little group of militia, couple of scientists and a heliotypist went upcoast in a spy-dirigible, took some prints from the air. Then some of them were lowered into the remains of Suroch to take some up-close shots.

“Sacramundi, the heliotypist, was so…appalled…he printed five hundred copies of his report at his own expense. Distributed it to bookshops gratis. Bypassed the mayor and Parliament, laid it out in front of the people…Mayor Turgisadi was screaming mad, but there was nothing he could do.

“There was demonstrations, then the Sacramundi Riots of ‘89. Pretty much forgotten now, but it damn-near brought the government down. A couple of the big concerns putting money into the Torque programme-Penton’s, that still owns the Arrowhead Mines, that was the biggest-anyway, they got scared and pulled out, and the thing collapsed.

“This, Yag my son,” Isaac indicated the book, “is why we ain’t using Torque.”

Yagharek slowly turned the pages. Sepia images of ruin passed before them.

“Ah…” Isaac brought his finger down on a drab panorama of what looked like crushed glass and charcoal. The heliotype was taken from very low in the air. A few of the larger shards that littered the enormous, perfectly circular plain were visible, suggesting that the desiccated debris was the remains of once-extraordinary twisted objects.

“Now this is what’s left of the heart of the city. That’s where they dropped the colourbomb in 1545. That’s what they said put an end to the Pirate Wars, but to be honest with you, Yag, they’d been over for a year before that, since New Crobuzon bombarded Suroch with Torque bombs. See, they dropped the colourbombs twelve months later to try to hide what they’d done…only one went into the sea and two didn’t work, so with only one left, they only cleared the central square mile or so of Suroch. These bits you can see…” He indicated low rubble at the edge of the circular plain. “From thereon out the ruins are still standing. That’s where you can see the Torque.”

He indicated that Yagharek should turn the page. Yagharek did so, and something clucked deep in his throat. Isaac supposed it was the garuda equivalent of a sudden intake of breath. Isaac looked briefly at the picture, then looked up, not too quickly, at Yagharek’s face.

“Those things in the background like melting statues used to be houses,” he said levelly. “The thing you’re looking at, as far as they could work out, is descended from the domestic goat. Apparently they used to keep them as pets in Suroch. This could be second, tenth, twentieth generation post-Torque, obviously. We don’t know how long they live.”

Yagharek stared at the dead thing in the heliotype.

“They had to shoot it, he explains in the text,” Isaac went on. “It killed two of the militia. They had a go at an autopsy, but those horns in its stomach weren’t dead, even though the rest of it was. They fought back, nearly killed the biologist. Do you see the carapace? Weird splicing going on there.” Yagharek nodded slowly.

“Turn the page, Yag. This next one, no one has the slightest idea what it used to be. Might have been spontaneously generated in the Torque explosion. But I think those gears there are descended from train engines.” He tapped the pages gently. “The…uh…best is yet to come. You haven’t seen the cockroach-tree, or the herds of what may once have been human.”

Yagharek was meticulous. He turned every single page. He saw furtive shots that had been stolen from behind walls, and vertiginous views from the air. A slow kaleidoscope of mutation and violence, petty wars fought between unfathomable monstrosities over no-man’s-lands of shifting slag and nightmare architecture.

“There were twenty militia, Sacramundi the heliotypist and three research scientists, plus a couple of engineers who stayed in the airship the whole time. Seven militia, Sacramundi and one chymist came out of Suroch. Some were Torque-wounded. By the time they got back to New Crobuzon one militiaman had died. Another had barbed tentacles where his eyes should be, and pieces of the scientist’s body were disappearing every night. No blood, no pain, just…smooth holes in her abdomen or arm or whatever. She killed herself.”

Isaac remembered first hearing the story told as an anecdote by an unorthodox history professor. Isaac had chased it up, following a trail of footnotes and old newspapers. The history had been forgotten, transmuted into emotional blackmail for children-“Be good or I’ll send you to Suroch where the monsters are!” It took a year and a half before Isaac saw a copy of Sacramundi’s report, and another three before he could match the price asked for it.

He thought he recognized some of the thoughts flickering almost invisibly under Yagharek’s impassive skin. They were the ideas every unorthodox undergraduate had at some time entertained.

“Yag,” Isaac said softly, “we ain’t going to use the Torque. You might be thinking ‘You still use hammers and some people are murdered with them.’ Right? Eh? ‘Rivers can flood and kill thousands or they can drive water turbines.’ Yes? Trust me…speaking as one who used to think the Torque was terribly exciting…it’s not a tool. It’s not a hammer, it’s not like water. It’s…the Torque is rogue power. We’re not talking crisis energy here, right? Get that right out of your head. Crisis is the energy underpinning the whole of physics. Torque’s not about physics. It’s not about anything. It’s…it’s an entirely pathological force. We don’t know where it comes from, why it appears, where it goes. All bets are off. No rules apply. You can’t tap it-well, you can try, but you’ve seen the results-you can’t play with it, you can’t trust it, you can’t understand it, you sure as godsdamn-fuck can’t control it.”

Isaac shook his head in irritation. “Oh sure, there’ve been experiments and whatnot, they reckon they’ve got techniques to shield from some effects, heighten others, and some of them might even work a little bit. But there’s never been a Torque experiment that didn’t end in…well, in tears, at the very least. As far as I’m concerned there’s only one kind of experiment we should be doing with Torque, and that’s how to avoid it. Either stop it in its tracks, or run like Libintos with the drakows on his tail.

“Five hundred years ago, a while after the Cacotopic Stain opened, there was a mild Torque storm that swept down from somewhere at sea, in the north-east. It hit New Crobuzon for a while.” Isaac shook his head slowly. “Nothing in the league of Suroch, obviously, but still enough for an epidemic of monstrous births and some very strange tricks of cartography. All the affected buildings were pulled down sharpish. Very sensible in my view. That’s when they drew up plans for the cloudtower-didn’t want to leave the weather to chance. But that’s broke now, and we’re fucked if we get any more random Torque currents. Fortunately, they seem to be getting rarer and rarer over the centuries. They sort of peaked around the 1200s.”