They had come perhaps one hundred yards from the sub. If there were no obstacles, they had more than four thousand yards to go. The team settled into a painful routine: walk a few dozen yards, stop and spread exotherms. While Nizhnimor and Haven rested, Unnerby and Underhill would look about for where the exotherms had found the richest fuel. From those spots, they would top off everyone's sludge panniers. Sometimes, there wasn't much fuel to be found (walking across a wide cement slab), and about all they had to shovel was airsnow. They needed that, too; they needed to breathe. But without fuel for the exotherms, the cold quickly became numbing, spreading in from the joints in the suits and up from their footpads. Then success depended on Sherkaner successfully guessing where to go next.

Actually, Sherkaner found that pretty easy. He'd gotten his bearings by the light of the burning tree, and by now the patterns of airsnow that concealed vegetation were obvious. Things were okay; he wasn't refreezing. The pain at the tips of his hands and feet was sharp, and every joint seemed to be a ring of fire, the pain of pressure-swelling, cold, and suit-chafe. Interesting problem, pain. So helpful, so obnoxious. Even the likes of Hrunkner Unnerby couldn't entirely ignore it; he could hear Unnerby's hoarse breath over the cable.

Stop, refill the panniers, top off the air, and then on again. Over and over. Gil Haven's frostbite seemed to be getting worse. They stopped, tried to rearrange the cobber's suit. Unnerby swapped places with Haven, to help Nizhnimor with the sled. "No problem, it's only the midhands," said Gil. But his labored breathing sounded much worse than Unnerby's.

Even so, they were still doing better than Sherk had expected. They trudged on through the Dark, and their routine soon became almost automatic. All that was left was the pain...and the wonder. Sherkaner looked out through the tiny portholes of his helmet. Beyond the swirl of mist and the exotherms' glow...there were gentle hills. It was not totally dark. Sometimes when his head was angled just right, he caught a glimpse of a reddish disk low in the western sky. He was seeing the sun of the Deepest Dark.

And through the tiny roof porthole, Sherkaner could see the stars.Weare here at last. The first to ever look upon the Deepest Dark. It was a world that some ancient philosophers had denied existence—for how can somethingbe, that can never be observed? But now it was seen. It did exist, centuries of cold and stillness...and stars everywhere. Even through the heavy glass of the porthole, even with only his topside eyes, he could see colors there that had never been seen in the stars before. If he would just stop for a while and angle all his eyes to watch, what more might he see? Most theorists figured the auroral patches would be gone without sunlight to drive them; others thought the aurora was somehow powered by the volcanoes that lived beneath them. There might be other lights here besides the stars... .

A jerk on the cable brought him back to earth. "Keep moving, gotta keep moving." Gil's voice was gasping. No doubt he was relaying from Unnerby. Underhill started to apologize, then realized that it was Amberdon Nizhnimor, back by the sled, who had paused.

"What is it?" Sherkaner asked.

"...Amber saw...light in the east....Keep moving."

East. To the right. The glass on that side of his helmet was fogged. He had a vague impression of a near ridgeline. Their operation was within four miles of the coast. Over that ridge they'd have a clear view of the horizon. Either the light was quite close or very far away. Yes! There was a light, a pale glow that spread sideways and up. Aurora? Sherkaner clamped down on his curiosity, kept putting one foot in front of another. But God below, how he wished he could climb that ridge and look across the frozen sea!

Sherkaner was a good little trouper right up to the next sludge stop. He was shoveling a glowing mix of exotherms, fuel, and airsnow into Haven's panniers when it happened. Five tiny lights raced into the western sky, leaving little corners here and there like some kind of slow lightning. One of the five faded to nothing, but the others drew quickly together and—lightblazed, so bright that Underhill's upward vision blurred in pain. But out to the sides, he could still see. The brightness grew and grew, a thousand times brighter than the faded disk of the sun. Multiple shadows showed stark around them. Still brighter and brighter grew the four lights, till Sherkaner could feel the heat soaking through the shell-cover of his suit. The airsnow all across the field burst upward in misty white-out brilliance. The warmth increased a moment more, almost scalding now—and then faded, leaving his back with the warm feeling you have when you walk into the shade on a Middle Years summer day.

The mists swirled around them, making the first perceptible wind they had experienced since leaving the sub. Suddenly it was very cold, the mists sucking warmth from their suits; only their boots were designed for immersion. The light was fading now, the air and water cooling to crystal and falling back to earth. Underhill risked focusing his upward eyes: The fierce points of light had spread into glowing disks, fading even as he watched. Where they overlapped, he saw a wavering and a folding, aurora-like; so they were localized in range as well as angle. Four, close set—the corners of a regular tetrahedron? So beautiful....But what was the range? Was this some kind of ball lightning, just a few hundred yards above the field?

In another few minutes they would be too faint to see. But there were other lights now, bright flashes beyond the eastern ridgeline. In the west, pinpricks of light slid faster and faster toward the zenith. A shimmering veil of light spread behind them.

The four Team members stood motionless. For an instant, Unnerby's soldier persona was blown away, and all that was left was awe. He stumbled away from the sled, and laid one hand on Sherkaner's back. His voice came faintly across the poor connection: "What is it, Sherkaner?"

"Don't know." He could feel Unnerby's arm trembling. "But someday we'll understand....Let's keep moving, Sergeant."

Like spring-driven marionettes suddenly kicked into motion, the Team finished loading up, and continued on their path. The show continued overhead, and though there was nothing like the four searing suns, the lights were more beautiful and extensive than any aurora ever known. Two moving stars slid faster and faster across the sky. The ghostly curtains of their passing spread all the way down to the west. Now high in the eastern sky, they flared incandescent, miniature versions of the first burning lights. As they dimmed and spread, legs of light crept down from their point of vanishment, brightening wherever they passed through the earlier glows.

The most spectacular movements were past now, but the slow wraithlike movement of light continued. If it was hundreds of miles up, like a true aurora, there was some immense energy source here. If it was just above their heads, maybe they were seeing the Deep Dark analogue of summer lightning. Either way, the show was worth all the risks of this adventure.

At last they reached the edge of Tiefer cantonment. The strange aurora was still visible as they started down the entrance ramp.

There had never been much question about the targets. They were the ones Underhill had originally imagined, the ones that Victory Smith came up with that first afternoon at Lands Command. If somehow they could reach the Deepest Dark, four soldiers and some explosives could do various damage to fuel dumps, to the shallow deepnesses of surface troops, perhaps even to Tiefstadt's general staff. Even these targets could not justify the research investment that Underhill was demanding.