A Deepness in the Sky by Vernor Vinge

library more than a year ago. Now his office consisted of a twenty-by-ten-by-four-foot slot in the dead space above the dormitory. The walls of the little room were covered with maps, the table with reams of teletype reports from landlines. Wireless communication had reached final failure some seventy days earlier. During the year before that the Crown's radiomen had experimented with more and more powerful transmitters, and there had been some hope that they would have wireless right up to the end. But no, all that was left was telegraphy and line-of-sight radio. Greenval looked at his visitor, certainly the last to Lands Command for more than two hundred years. "So, Colonel Smith, you just got back from the East. Why don't I hear any huzzahs from yourself? We've outlasted the enemy."
    Victory Smith's attention had been caught by the General's periscope. It was the reason Greenval had stuck his cubbyhole up here—a last view upon the world. Royal Falls had stilled more than two years ago. She could see all the way up the valley. A dark land, covered now with an eldritch frost that formed endlessly on rock and ice alike. Carbon dioxide, leaching out of the atmosphere.But Sherkaner will see a world far colder than this.
    "Colonel?"
    Smith stepped back from the periscope. "Sorry, sir....I admire the Diggers with all my heart."At least the troops who are actually doing thedigging. She had been in their field deepnesses. "But it's been days since they could reach any enemy positions. Less than half will be in fighting form after the Dark. I'm afraid that Digger Command guessed the stand-down point wrong."
    "Yeah," grumpily. "Digger Command makes the record book for longest sustained operations, but the Tiefers gained by quitting just when they did." He sighed and said something that might have gotten him cashiered in other circumstances, but when you're five years past the end of the world, there aren't a lot of people to hear. "You know, the Tiefers aren't such a bad sort. Take the long view and you'll see nastier types in some of our own allies, waiting for Crown and Tiefstadt to beat each other into a bloody pulp. That's the place where we should be doing our planning, for the next baddies that are going to come after us. We're going to win this war, but if we have to win it with the tunnels and the Diggers, we'll still be fighting for years into the New Sun."
    He gave his aromatique an emphatic crunch and jabbed a forehand at Smith. "Your project is our only chance to bring this to a clean end."
    Smith's reply was abrupt. "And the chances would have been still better if you had let me stay with the Team."
    Greenval seemed to ignore the complaint. "Victory, you've been with this project for seven years now. Do you really think it can work?"
    Maybe it was the stale air, making them all daft. Indecision was totally alien to the public image of Strut Greenval. She had known him for nine years. Among his closest confidants, Greenval was an open-minded person—up to the point where final decisions had to be made. Then he was the man without doubt, facing down ranks of generals and even the King's political advisors. Never had she heard such a sad, lost question coming from him. Now she saw an old, old man who in a few hours would surrender to the Dark, perhaps for the last time. The realization was like leaning against a familiar railing and feeling it begin to give way. "S-sir, we have selected our targets well. If they are destroyed, Tiefstadt's surrender should follow almost immediately. Underhill's Team is in a lake less than two miles from the targets." And that was an enormous achievement in itself. The lake was near Tiefstadt's most important supply center, a hundred miles deep in Tiefer territory.
    "Unnerby and Underhill and the others need only walk a short distance, sir. We tested their suits and the exotherms for much longer periods in conditions almost as—"
    Greenval smiled weakly. "Yes, I know. I jammed the numbers