“What’s happening to the walls?” Mal called from above. She had stopped, the panicking rodents flooding past her on both sides, while Khan led them upwards like the Pied Piper.

“Walls…?” But there was daylight crawling in ragged tears and cracks through the concrete of the fire escape. Its very substance was attenuating until there was nothing but air, the steps beneath Lee’s feet abruptly only a likelihood rather than the hard certainty she would have preferred.

“Up!” cried the Nissa woman despairingly. Mal had Lee’s wrist, Sabreur had her other elbow, and they hauled her upwards, towards the higher floors. Here the regular number of dimensions still reigned. Below, soldiers were pushing past the Nissa woman as she stood there trying to make her device work, trying to bar the way. You shall not pass.

Oh. Lee knew how that one went.

Three storeys of wall disappeared beside them, and Lee put on a burst of speed, dragging Mal with her. But what should have been open air…was not open. She saw a honeycomb of girderwork, compartments, ducts—a cut-away diagram of the airship’s decks as it overlapped impossibly with the tower. Sabreur pulled his friend up, then the lead soldier, then the next. Every space was thronging with uniformed rodent soldiers, waiting to intersect with their reality.

She didn’t know if someone gave the order to fire or whether the situation simply accelerated of its own accord. But the soldiers below were now shooting into that impossible, slewing vista, and the rodents were firing back. Lee caught wild glimpses of carnage on both sides, shredded bodies caught point-blank with nowhere to hide as the walls of reality simply ghosted away. She saw buckling infrastructure, shattered concrete. The building and the vessel were fighting over the space, letting shrapnel and shot fly both ways through a breach in reality that a bus could have driven through.

The Nissa woman presented her device like a talisman and a shearing blade of flechettes carved into her, sending her tumbling into—through—the wall that should have been behind her. She fell through a cluttered void that couldn’t make up its mind about what world it was in.

There was a deep, groaning sound, and Lee abruptly understood that this wasn’t just some theoretical duelling of realities. The tower’s very structure was under attack. There must be fissures racing through every part of it—and they were heading for the top.

“Southall! Up, man! Keep going up!” Sabreur yelled. Lee saw a flechette strike near him, shattering an emergency light.