“Shuttle away. Time until first torpedo impact, seven minutes and forty-two seconds.”

“Turn over and activate the defence grid.”

“Turning now.”

The crushing deceleration ceased. Suddenly weightless, I lurched forward against my straps. My head came down and my mouth snapped shut. I felt a sharp pain and my mouth filled with the metallic taste of blood.

The Trouble Dog pivoted through 180 degrees, until its bow faced the direction we were moving in, and then the engines kicked in again, accelerating us towards the incoming threat.

“Cannons active.”

The ship rang with a popcorn clatter as the point-defence batteries sprayed tracer rounds at the Fenrir’s torpedoes.

Moving with effort under acceleration, I put my fingers to my mouth. The tips came away bright red. Hurled forwards, I had bitten myself hard, and sunk my front teeth almost completely through my lower lip. It stung like hell.

I glanced across at Laura Petrushka, and saw agony written across her features. “Are you okay?”

“It’s my leg.” She put a hand to the inflatable cast on her thigh. “The pressure. It hurts.” She spoke one word at a time, punctuating each with a sharp intake of breath. “I can feel the bone coming apart, again.”

“I’m sorry,” I told her, “but there’s not much I can do right now.”

“It’s not your fault.”

I swivelled my eyes back to the screen, my attention caught by a bright flash.

“One torpedo down,” the Trouble Dog reported. “Two more still on course.”

“How’s the shuttle doing?” Speaking hurt my battered jaw.

“Five minutes from the surface.”

“Anything targeting it?”

“Nothing yet.”

I gave the tactical display a squint. The Fenrir was a red dot ahead and slightly above us, coming in on a trajectory that would intersect our own in a matter of minutes. If she got past us, the shuttle would be defenceless.

“Stand by to provide covering fire if necessary.”

“Roger.” The tone still hadn’t changed. We could have been discussing the weather for all the expression she showed. “Four birds in their tubes and ready to fly on your mark.”

I watched the Brain’s carved surface roll beneath us. Another of the Fenrir’s torpedoes died in a burst of white.

“Shuttle entering the atmosphere.”

“No sign it’s being targeted?”

“No, why should there be?” For the first time, the Trouble Dog let an exasperated tinge bleed into her voice. “I’m the only danger here. She has to deal with me first. Once I’m gone, the shuttle’s stranded. Fenrir can pick it off at her leisure.”

I felt a wave of helplessness. These duelling metal beasts could out-think and out-react me. No wonder the Dog sounded impatient.

“What do you suggest?”

“We can’t win in a stand-up fight.”

“So?”

“So we run for cover. Change the rules of engagement. Hide, and fight back as and when the opportunity presents itself.”

“Guerrilla rules?”