Rachel Sexton felt a growing chill inside as she moved down the ice sheet into a deepening night. Disquieting images swirled in her mind-the meteorite, the phosphorescent plankton, the implications if Norah Mangor had made a mistake with the ice cores.

A solid matrix of freshwater ice, Norah had argued, reminding them all that she had drilled cores all around the area as well as directly over the meteorite. If the glacier contained saltwater interstices filled with plankton, she would have seen them. Wouldn't she? Nonetheless, Rachel's intuition kept returning to the simplest solution.

There are plankton frozen in this glacier.

Ten minutes and four flares later, Rachel and the others were approximately 250 yards from the habisphere. Without warning, Norah stopped short. "This is the spot," she said, sounding like a water-witch diviner who had mystically sensed the perfect spot to drill a well.

Rachel turned and glanced up the slope behind them. The habisphere had long since disappeared into the dim, moonlit night, but the line of flares was clearly visible, the farthest one twinkling reassuringly like a faint star. The flares were in a perfectly straight line, like a carefully calculated runway. Rachel was impressed with Norah's skills.

"Another reason we let the sled go first," Norah called out when she saw Rachel admiring the line of flares. "The runners are straight. If we let gravity lead the sled and we don't interfere, we're guaranteed to travel in a straight line."

"Neat trick," Tolland yelled. "Wish there were something like that for the open sea."

This IS the open sea, Rachel thought, picturing the ocean beneath them. For a split second, the most distant flame caught her attention. It had disappeared, as if the light had been blotted out by a passing form. A moment later, though, the light reappeared. Rachel felt a sudden uneasiness. "Norah," she yelled over the wind, "did you say there were polar bears up here?"

The glaciologist was preparing a final flare and either did not hear or was ignoring her.

"Polar bears," Tolland yelled, "eat seals. They only attack humans when we invade their space."

"But this is polar bear country, right?" Rachel could never remember which pole had bears and which had penguins.

"Yeah," Tolland shouted back. "Polar bears actually give the Arctic its name. Arktos is Greek for bear."

Terrific. Rachel gazed nervously into the dark.

"Antarctica has no polar bears," Tolland said. "So they call it Anti-arktos."

"Thanks, Mike," Rachel yelled. "Enough talk of polar bears."

He laughed. "Right. Sorry."

Norah pressed a final flare into the snow. As before, the four of them were engulfed in a reddish glow, looking bloated in their black weather suits. Beyond the circle of light emanating from the flare, the rest of the world became totally invisible, a circular shroud of blackness engulfing them.

As Rachel and the others looked on, Norah planted her feet and used careful overhand motions to reel the sled several yards back up the slope to where they were standing. Then, keeping the rope taut, she crouched and manually activated the sled's talon brakes-four angled spikes that dug into the ice to keep the sled stationary. That done, she stood up and brushed herself off, the rope around her waist falling slack.

"All right," Norah shouted. "Time to go to work."

The glaciologist circled to the downwind end of the sled and began unfastening the butterfly eyelets holding the protective canvas over the gear. Rachel, feeling like she had been a little hard on Norah, moved to help by unfastening the rear of the flap.

"Jesus, NO!" Norah yelled, her head snapping up. "Don't ever do that!"

Rachel recoiled, confused.

"Never unfasten the upwind side!" Norah said. "You'll create a wind sock! This sled would have taken off like an umbrella in a wind tunnel!"

Rachel backed off. "I'm sorry. I… "

She glared. "You and space boy shouldn't be out here."

None of us should, Rachel thought.

Amateurs, Norah seethed, cursing the administrator's insistence on sending Corky and Sexton along. These clowns are going to get someone killed out here. The last thing Norah wanted right now was to play baby-sitter.

"Mike," she said, "I need help lifting the GPR off the sled."

Tolland helped her unpack the Ground Penetrating Radar and position it on the ice. The instrument looked like three miniature snowplow blades that had been affixed in parallel to an aluminum frame. The entire device was no more than a yard long and was connected by cables to a current attenuator and a marine battery on the sled.

"That's radar?" Corky asked, yelling over the wind.

Norah nodded in silence. Ground Penetrating Radar was far more equipped to see brine ice than PODS was. The GPR transmitter sent pulses of electromagnetic energy through the ice, and the pulses bounced differently off substances of differing crystal structure. Pure freshwater froze in a flat, shingled lattice. However, seawater froze in more of a meshed or forked lattice on account of its sodium content, causing the GPR pulses to bounce back erratically, greatly diminishing the number of reflections.

Norah powered up the machine. "I'll be taking a kind of echo-location cross-sectional image of the ice sheet around the extraction pit," she yelled. "The machine's internal software will render a cross section of the glacier and then print it out. Any sea ice will register as a shadow."

"Printout?" Tolland looked surprised. "You can print out here?"

Norah pointed to a cable from the GPR leading to a device still protected under the canopy. "No choice but to print. Computer screens use too much valuable battery power, so field glaciologists print data to heat-transfer printers. Colors aren't brilliant, but laser toner clumps below neg twenty. Learned that the hard way in Alaska."

Norah asked everyone to stand on the downhill side of the GPR as she prepared to align the transmitter such that it would scan the area of the meteorite hole, almost three football fields away. But as Norah looked back through the night in the general direction from which they had come, she couldn't see a damn thing. "Mike, I need to align the GPR transmitter with the meteorite site, but this flare has me blinded. I'm going back up the slope just enough to get out of the light. I'll hold my arms in line with the flares, and you adjust the alignment on the GPR."

Tolland nodded, kneeling down beside the radar device.

Norah stamped her crampons into the ice and leaned forward against the wind as she moved up the incline toward the habisphere. The katabatic today was much stronger than she'd imagined, and she sensed a storm coming in. It didn't matter. They would be done here in a matter of minutes. They'll see I'm right. Norah clomped twenty yards back toward the habisphere. She reached the edge of the darkness just as the belay rope went taut.

Norah looked back up the glacier. As her eyes adjusted to the dark, the line of flares slowly came into view several degrees to her left. She shifted her position until she was perfectly lined up with them. Then she held her arms out like a compass, turning her body, indicating the exact vector. "I'm in line with them now!" she yelled.

Tolland adjusted the GPR device and waved. "All set!"

Norah took a final look up the incline, grateful for the illuminated pathway home. As she looked out, though, something odd occurred. For an instant, one of the nearest flares entirely disappeared from view. Before Norah could worry that it was dying out, the flare reappeared. If Norah didn't know better, she would assume something had passed between the flare and her location. Certainly nobody else was out here… unless of course the administrator had started to feel guilty and sent a NASA team out after them. Somehow Norah doubted it. Probably nothing, she decided. A gust of wind had momentarily killed the flame.

Norah returned to the GPR. "All lined up?"

Tolland shrugged. "I think so."

Norah went over to the control device on the sled and pressed a button. A sharp buzz emanated from the GPR and then stopped. "Okay," she said. "Done."

"That's it?" Corky said.

"All the work is in setup. The actual shot takes only a second."

Onboard the sled, the heat-transfer printer had already begun to hum and click. The printer was enclosed in a clear plastic covering and was slowly ejecting a heavy, curled paper. Norah waited until the device had completed printing, and then she reached up under the plastic and removed the printout. They'll see, she thought, carrying the printout over to the flare so that everyone could see it. There won't be any saltwater.

Everyone gathered around as Norah stood over the flare, clutching the printout tightly in her gloves. She took a deep breath and uncurled the paper to examine the data. The image on the paper made her recoil in horror.

"Oh, God!" Norah stared, unable to believe what she was looking at. As expected, the printout revealed a clear cross section of the water-filled meteorite shaft. But what Norah had never expected to see was the hazy grayish outline of a humanoid form floating halfway down the shaft. Her blood turned to ice. "Oh God… there's a body in the extraction pit."

Everyone stared in stunned silence.

The ghostlike body was floating head down in the narrow shaft. Billowing around the corpse like some sort of cape was an eerie shroudlike aura. Norah now realized what the aura was. The GPR had captured a faint trace of the victim's heavy coat, what could only be a familiar, long, dense camel hair.

"It's… Ming," she said in a whisper. "He must have slipped…."

Norah Mangor never imagined that seeing Ming's body in the extraction pit would be the lesser of the two shocks the printout would reveal, but as her eyes traced downward in the shaft, she saw something else.

The ice beneath the extraction shaft…

Norah stared. Her first thought was that something had gone wrong with the scan. Then, as she studied the image more closely, an unsettling realization began to grow, like the storm gathering around them. The paper's edges flapped wildly in the wind as she turned and looked more intently at the printout.

But… that's impossible!

Suddenly, the truth came crashing down. The realization felt like it was going to bury her. She forgot all about Ming.

Norah now understood. The saltwater in the shaft! She fell to her knees in the snow beside the flare. She could barely breathe. Still clutching the paper in her hands, she began trembling.

My God… it didn't even occur to me.

Then, with a sudden eruption of rage, she spun her head in the direction of the NASA habisphere. "You bastards!" she screamed, her voice trailing off in the wind. "You goddamned bastards!"

In the darkness, only fifty yards away, Delta-One held his CrypTalk device to his mouth and spoke only two words to his controller. "They know."