Cirocco sneezed, and snow fluttered away. It was very light,, very dry snow, and it had drifted into every crevice of her blanket. She sat up, and it avalanched into her lap.

Icicles hung from the edges of the tarp and the ropes that suspended her hammock. There was a constant cracking sound as wind whipped branches up and down, and a constant clatter of ice hitting the frozen tarp. One of her hands was exposed, and it was stiff and chapped as she reached across the gap and prodded Gaby.

"Huh? Huh?" Gaby looked around with one bleary eye, the other held shut by frozen lashes. "Oh, damn!" She was racked by coughs.

"Are you okay?"

"Except for a frozen ear, I guess so. What now?"

"Put on everything we have, I guess. Then wait it out."

It was hard to do, sitting in a hammock, but they managed it. There was one disaster as Cirocco fumbled with numb fingers, then saw a glove quickly vanish in the swirling snow beneath them. She cursed for five minutes before recalling they still had Gene's gloves.

Then they waited.

Sleep was impossible. They were warm enough in the layers of clothing and blankets, but they wished for face masks and goggles. Every ten minutes they shook the accumulation of snow from their bodies.

They tried to talk, but the spoke was alive with sound. Cirocco found the minutes stretching into hours as she reclined with the blanket over her face and listened to the wind howling. Over that sound, and much more frightening, was a sound like pop- ping corn. Branches, overloaded with ice, were snapping off as the wind whipped them.

.They waited five hours. If anything, the wind grew colder and stronger. A branch snapped near them, and Cirocco listened to it crash through the ice-crusted forest below.

"Gaby, can you hear me?"

"I hear you, Captain. What do we do now?"

"I hate to say it, but we're going to have to move. I want to be on thicker branches. I don't think these will break, but if one breaks above us, we've had it."

"I was just waiting for you to suggest it."

Getting out of the hammocks was a nightmare. Once out of them and standing on the tree limb, it was worse. Their safety ropes were frozen and had to be painstakingly bent and twisted before they could be used. When they began to work their way in, it was strictly one step at a time. They had to attach a second safety line before going back to remove the first, then repeat the process, tying knots with gloved hands or removing the gloves and doing it quickly before their fingers grew numb. They used hammers and picks to chip ice from branches they had to walk on. With all their caution, Cirocco fell twice and Gaby once. Cirocco's second fall resulted in a strained muscle in her back when the safety line stopped her.

After an hour of struggle they reached the main trunk. It was steady and wide enough to sit on. But the wind blew harder than ever with no branches to break its force.

They drove spikes into the tree, lashed themselves to it, and prepared once more to wait it out.

"I hate to bring this up, but I can't feel my toes."

Cirocco coughed for a long time before she could talk. "What do you suggest?"

"I don't know," Gaby said. "I do know that we'll freeze to death if we don't do something. We've got to either keep moving, or look for shelter. "

She was right, and Cirocco knew it. "Up, or down?"

"There's the staircase at the bottom."

"It took us a day to get this high, with no ice to complicate things. And it's another two days back to the stairs. If the entrance isn't buried in snow."

"I was about to get to that."

"If we move, we might as well go up. Either way, we'll freeze unless this weather breaks soon. Moving would postpone that a while, I guess."

"T'hat was my thought, too," Gaby said. "But I'd like to try something else, first. Let's go all the way to the wall. Remember earlier you talked about where the angels might live, and you mentioned caves. Maybe there's caves back there."

Cirocco knew the main thing was to become active again, to get the blood flowing. So they crawled along the tree trunk, chipping ice as they went. In fifteen minutes they reached the wall.

Gaby studied it, then braced herself and began attacking the ice with her pick. It fell away to expose the gray substance, but she did not stop chopping. When Cirocco saw what she was doing, she joined her with her own pick.

It went well for a while. They hacked a hole half a meter in diameter. The white milk froze as it oozed from the wall, and they chipped that away, too. Gaby was a demon of snow; it caked her clothes and the woolen scarf drawn over her mouth and nose, turned her eyebrows into thick white ledges.

Soon they reached a new layer that was too tough to cut. Gaby attacked it viciously, but eventually conceded she was getting nowhere. She let her hand drop to her side and glared at the wall.

"Well, it was an idea." She kicked disgustedly at the snow that had fallen around them as they worked, shaken down by the vibrations. She looked at it, then craned her neck and stared up into the darkness. She took a step back, grabbing Cirocco's arm to steady herself when she slipped on ice chips.

"There's a darker patch up there," she said, pointing. "Ten ... no, fifteen meters up. Slightly to the right. See it?"

Cirocco was not sure. She could see several dark places, but none of them looked like a cave.

"I'm going up to take a look."

"Let me do it. You've been working harder." Gaby shook her head. "I'm lighter."

Cirocco did not argue, and Gaby hammered a spike into the wall as high as she could reach. She tied a rope to it and climbed high enough to hammer in a second spike. When it was secure, she knocked the first one loose and drove it in a meter above the second.

It took her an hour to reach the place. Cirocco shivered below, stamping her feet and shrugging off the showers of ice Gaby sent down around her. Then a dislodged shelf of snow broke over her shoulders and brought her to her knees.

"Sorry about that!" Gaby called down. "But I've got something here. Let me get it cleared and you can come up."

The entrance was barely large enough for Cirocco to squeeze through, even after Gaby had chipped away most of the ice. In- side, it was a hollow bubble with a diameter of about a meter and a half, and a floor to ceiling height slightly less than that. Cirocco had to remove her pack, then pull it in after her. With both of them and two packs inside it seemed possible they might have found room to stow a shoebox and still be able to breathe, but not much more than that.

"Cozy, eh?" Gaby asked, removing Cirocco's elbow from her neck.

"Sorry. Oh, sorry about that, too. Gaby, my foot!"

"Excuse me. If you'd just scrunch... that's better, but I wish you wouldn't stand there."

"Where? Oh, my." She suddenly burst out laughing. She was crouched with her back against the ceiling and her knees bent while Gaby edged to the rear and tried to stay out of the way.

"What's so funny?"

"I was thinking of an old movie. Laurel and Hardy in their nightgowns, trying to bed down in an upper berth."

Gaby was smiling, but obviously didn't know what she was talking about.

"An upper berth, you know, on a cross-country train ... Skip it. I just thought they should have tried it in arctic gear, and With a couple suitcases thrown in. How do you want to work this?"

They shoveled the remainder of the snow out of the tiny cave and stacked the gear in front of the opening to block it. When they did so, what little light there had been vanished, but the wind stopped blowing in, so they counted it a gain. After struggling for twenty minutes they managed to settle down side by side. Cirocco could barely move, but was not inclined to worry about such things in the blessed warmth.

"You think we can get some sleep now?" Gaby wondered. "I sure feel like I could. How are your toes?" "Okay. Tingling, but they're getting warm."

"Me, too. Good night, Gaby." She hesitated only a moment, then leaned over and kissed her.

"I love you, Rocky."

"Go to sleep." She said it with a smile.

The next time Cirocco woke, sweat beaded her forehead. Her clothes were soaked. She lifted her head groggily and realized she could see. Wondering if the weather had changed, she moved her pack slightly, then more urgently, and discovered the en- trance to the cave had closed.

She almost woke Gaby, but thought better of it just in time.

"Try to get out first," she muttered. There was no sense telling Gaby she had been eaten alive again unless it was really true. Gaby would not take the news wells the thought of being confined in such a small space-bad enough in itself-was terrifying when she thought of Gaby and her contagious panic.

It turned out there was no cause for alarm. While she explored the wall where the hole had been, it began to move, irising until it was, as large as it had been before. There was a clear window of ice with faint light behind it. She hit it with her gloved fist and it shattered. Frigid air rushed in, and she hastily blocked the hole again with her pack.

in a few minutes she moved the pack. The hole had closed to a few centimeters.

She looked thoughtfully at the tiny hole, putting it all together in her mind. Only when she thought she understood it did she shake Gaby's shoulder.

"Wake up, kid, it's time to make adjustments again."

"Hmmm?" Gaby came awake quickly. "Hell, it's an oven in here."

"That's what I meant. We'll have to take off some clothes. You want to go first? "

"Go ahead. I'll try to stay out of your way."

"Right. Why do you suppose it's so hot in here? Have you thought about that? "

"I just woke up, Rocky. Have a heart."

"Okay. I'll tell you. Feel the walls." She performed the complex task of removing her parka while Gaby made the same discovery she had made earlier.

"It's warm."

"Yeah. I couldn't figure out this wall from the first. I thought the trees were unplanned-for, like the growths on the cable, but they couldn't grow here, as I see it, without the wall to nourish them. I tried to think what kind of machine would do that best, and I came back to a natural biochemical machine. An animal, or plant, possibly a genetically tailored one. I find it hard to believe something like this could have evolved in any reasonable time. It's 300 kilometers high, hollow in the middle, and hugs the real wall."