The rat-soldiers were leaping from their airship to the tower. Some fell towards the London streets, through shattering concrete, or away—hurtling into an abyss Lee had no name for. A handful of Julian’s soldiers were shooting down into them, but there were more flooding over as they left the sinking airship. She turned and ran. The leader of the soldiers was yelling at Sabreur to “Just go! Get up top!”

The fire escape ran all the way to the roof. And by the time Lee arrived, Khan and the translator had the door open and the fugitive rats were spilling out into the wild, chill air. All around, the building was undergoing renewed assault: partly physical collision, partly existential crisis. Space that was tower block in human London was being randomly replaced with empty air from the rats’ world. Lee looked out across the morning-lit city with Mal, expecting a fleet of rescue helicopters to power over the capital like something out of Apocalypse Now.

But the sky was empty.

“What now?” she shouted, as the tower groaned in torment and listed slightly but noticeably. She imagined cracks spidering through every concrete beam, only the twisted cores of steel holding everything together. “You!” she yelled at Sabreur. “You said there’d be helicopters.”

III

Julian looked at Pryor blankly. I should have bloody well arrested you when I had the chance. “There will be helicopters. They’re on their way,” he said, because he still felt it was his job to tell reassuring falsehoods. Past the lip of the roof, he saw the impossible bulk of the rodent flying machine, a vast dreadnaught now fatally entangled with their tower and half a dozen neighbouring spires. It was raining glass onto London’s streets, and he hoped to hell that Royce had reached cover—and that his men had made some headway in evacuating the area.

“Christ,” he choked. Alison squeezed his arm reassuringly, but it didn’t help. There must be tens dead, hundreds. A thousand phone cameras would be recording the architectural carnage. The eyes of the world would already have seen the worst. Julian risked a glance back down the stairwell.

“Southall!” he called.

But to his horror the rat troopers were swarming the stairs, and the humans on the roof hadn’t a weapon between them.

“Get back from the door!” he shouted, slamming it shut. The building shuddered and groaned, like a thing in pain. Everyone lurched towards the nearest edge, and he could hear their adopted rat-creatures’ high-pitched screaming.

“Kay!” He found her crouched in their midst. He half expected her to be lighting up, or to make a sardonic comment, but her eyes were wild with fear and she just shook her head.

His phone went. Without taking his eyes from the door to the fire escape, he answered.

“Julian, what’s your situation?” Hind’s voice.

“We’re on the roof.” He felt he was being creditably calm, under the circumstances.