I can barely breathe, let alone stay upright, my head filled with ringing. Another panel slides back and a second automatic gun appears, smoke billowing around it. When it swings down to aim at me, there is nothing I can do.

A rumble, a glare of light and the beam swings away, pointing up at a dark shape that drops from the sky, flying terrifyingly close to the walls of the canyon. It’s the Charis.

Silas! I try to shout, but there is no air in my lungs, and I watch in horror as the Slug opens fire, punching holes in the Charis’s belly, sending her pin-balling from one rock wall to another.

Then from above there’s a sudden clank, and streams of water cascade from the Charis’s cooling tanks, putting out the fires that smoulder on her body, throwing the beams off course in the cloud of vapour and dust. Water hits me too, and though I gasp at the shock, it clears my head, giving me a last burst of energy.

As the Charis rises rapidly from the canyon, out of the line of fire, I wrench at the coupling that joins the wagons together. But it’s useless, the thing is solid metal, the hydraulic screws locked tight and without my pistol…

There’s a cry. Turning my head in the rushing air, I see a mare racing alongside me once again. It struggles to keep speed, overloaded with G’hals; Rat is driving, Bui is balancing on the seat and behind her, bloodied and torn but alive, are Malady Falco and Pegeen.

‘Move!’ Bui bellows, as the automatic gun spins. On her shoulder is a blaster. With my last strength, I scramble back onto the Slug’s platform and cover my head as she pulls the trigger.

The explosion smashes into me, sending shards of hot metal and burning plastic flying. The coupling blows with an ear-splitting shriek and – with a crash that nearly sends me plummeting from the side – the Slug is free. I look up to see the rest of the Air Line carriages speeding away, the distance already increasing. On the mare, Bui aims the blaster once more, this time at the automatic gun.

The explosion shakes the Slug violently, and acrid smoke pours from the apertures, like a creature heaving out its dying breaths. A second later the door flies open and a gunner staggers onto the platform.

I trip them up, throwing them from the edge. Bui is ready; she pulls a smoke grenade from her coat and throws it towards me. I catch it and – before anyone can figure out what is happening – toss it inside the body of the Slug.