He looked down the dark tunnel.

Smooth fused floor, smooth arched walls, the tunnel went on into the mountain side. Blast doors made ribs along the tunnel sides, their tracks and slots carved across the floor and roof. He could see the elevator-shaft doors, and the boarding point for the service-tube capsules. He walked along, past the sets of ancient blast door6, until he came to the access shafts. The elevators were all at the bottom; the transit tube was locked shut. No power seemed to be running through any of the systems. He turned and walked back to the accommodation section, through it and past the bodies and the flyer without giving them a glance, and eventually out into the open air.

He sat down at the side of the tunnel entrance, in the snow, his back to the rock. They saw him from the CAT, and Yalson said, "Horza! Are you all right?"

"No," he said, turning the laser rifle off. "No, I'm not."

"What's wrong?" Yalson said quickly. Horza took the suit helmet off, putting it down on the snow beside him. The cold air sucked heat from his face, and he had to breathe hard in the thin atmosphere.

"There is death here," he said to the cloudless sky.

"It's called a batholith: a granitic intrusion which rose up like a molten bubble into the sedimentary and metamorphic rocks already here a hundred million years ago.

"Eleven thousand years ago the locals built the Command System in it, hoping to use the rock cover as protection from fusion warheads.

"They built nine stations and eight trains. The idea was that the politicos and military chiefs sat in one train, their seconds-in-command and deputies in another, and during a war all eight trains would be shuffled around the tunnels, halting in a station to be linked via hardened communication channels to the transceiver sites on the immediate surface and throughout the state, so they could run the war. The enemy would have a hard time cracking the granite that deep anyway, but hitting something as relatively small as a station would be even more difficult, and they never could be sure there would be a train in it, or that it would be manned, and on top of that they had to knock out the back-up train as well as the main one.

"Germ warfare killed them all off, and some time between then and ten thousand years ago the Dra'Azon moved in, pumping the air out of the tunnels and replacing it with inert gas. Seven thousand years ago a new ice age started, and about four thousand years after that the place got so cold Mr Adequate pumped the argon out and let the planet's own atmosphere back in; it's so desiccated, nothing's rusted in the tunnels for three millennia.

"About three and a half thousand years ago the Dra'Azon came to an agreement with most of the rival Galactic Federations which allowed ships in distress to cross the Quiet Barriers. Politically neutral, relatively powerless species were permitted to set up small bases on most of the Planets of the Dead to provide help for those in distress and — I suppose — to provide a sop to the people who had always wanted to know what the planets were like; certainly on Schar's World, Mr Adequate let us take a good look at the System every year, and turned a blind eye when we went down unofficially. However nobody's ever taken unscrambled recordings of any sort out of the tunnels.

"The entrance we're at is here: at the base of the peninsula, above station four, one of the three main stations — the others are one and seven — where repair and maintenance facilities exist. There are no trains parked in four, three or five. There are two trains in station one, two in seven, one train each in the rest. At least that's where they ought to be; the Idirans may have moved them, though I doubt it.

"The stations are twenty-five to thirty-five kilometres apart, linked by twin sets of tunnels which only join up at each of the stations. The whole System is buried about five kilometres down.

"We'll take lasers… and a neural stunner, plus chaff grenades for protection — nothing heavier. Neisin can take his projectile rifle; the bullets he has are only light explosive… But no plasma cannons or micronukes. They'd be dangerous enough in the tunnels anyway, God knows, but they might also bring down Mr Adequate's wrath, and we don't want that.

"Wubslin's rigged up our ship mass anomaly sensor into a portable set, so we can spot the Mind. In addition, I've got a mass sensor in my suit, so we shouldn't have any problem actually finding what we're after, even if it's hidden itself-"

"Assuming the Idirans don't have their own communicators, they'll be using the Changers'. Our transceivers cover their frequencies and more, so we can listen in on them, but they can't hear us.

"So those are the tunnels. That Mind is in there somewhere, and so, presumably, are some Idirans and medjel."

Horza stood in the mess room at the head of the table, under the screen. On the screen a diagram of the tunnels was superimposed over a map of the peninsula. The others looked at him. The empty semi-suit of the medjel he had found lay in the centre of the table.

"You want to take us all in?" the drone Unaha-Closp said.

"Yes."

"What about the ship?" Neisin said.

"It can take care of itself. I'll programme its automatics so that it'll recognise us and defend itself against anybody else."

"And you're going to take her?" Yalson asked, nodding at Balveda, who was sitting opposite her.

Horza looked at the Culture woman. "I'd prefer to have Balveda where I can see her," he said. "I wouldn't feel safe leaving her here with any of you."

"I still don't see why I have to go," Unaha-Closp said.

"Because," Horza told it, "I don't trust you on board here, either. Besides, I want you to carry stuff."

"What?" The drone sounded angry.

"I don't know that you're being completely honest here, Horza," Aviger said, shaking his head ruefully. "You say that the Idirans and medjel… well, that you're on their side. But here they are, and they've killed four of your own people already, and you think that they're somewhere inside these tunnels, wandering about… And they're supposed to be about the best ground-troops in the galaxy. You want to send us up against them?"

"First of all," Horza sighed, "I am on their side. We're after the same thing. Secondly, it looks to me as though they don't have many weapons of their own, otherwise that medjel would certainly have been armed. All they probably have here are the Changers" weapons. Also it looks, from this medjel suit we've got" — he gestured at the webbed apparatus in the middle of the table, which he and Wubslin had been studying since they had brought it on board — "like a lot of their equipment is blown. Only the lights and the heaters on this thing were working. Everything else had fused. My guess is all that happened when they came through the Quiet Barrier. They were all zapped inside the chuy-hirtsi, and their battle gear was fucked up. If the same thing happened to their weapons as happened to their suits, they're virtually unarmed, and with a lot of problems. With all these fancy new AG harnesses and lasers, we're much better equipped, even in the unlikely event that it does come to a fight."

"Which is very likely, considering they won't have any communicators left," Balveda said. "You'll never get close enough to tell them. And even if you did, how are they supposed to know you're who you say you are? If they're the same lot you think they are, they came in here just after the Mind did; they won't even have heard of you. They certainly won't believe you." The Culture agent looked round the others. "Your surrogate captain is leading you to your deaths."