In the corridor formed by the protection of the root system holding back the soil, darkness stretching before and behind them, the five treaded a long journey following the light of the firefly. The air was humid and had been warm, but in the process of their walk had gradually become chilly, much like a cave or true basement. While the library's complex was indeed large, he thought they must have long ago walked past its limits, and yet nothing had changed and the root-bound tunnel continued threading in a twisting line through the earth. He provided his standard-colored flame and Azula, two places behind him, her own blue. The repetition as they crawled over laced roots and ducked slipping through organic turns was mesmerizing between the three light sources. By that time Zuko could sense the firefly itself as if it were a small fleck of flame, the same as the true fire of life the dragons had taught, and he was certain that, like the foxes, if it had once been a natural creature it was no longer so but had been enhanced by the spirit magic provided by the owl.

The tunnel remained provisioned widely enough for their passing and never dithered or turned into dead ends. The firefly was leading them safely and truly, but he couldn't imagine where. He'd thought at first it may be an armory, or a tomb of clay soldiers they could take command of, but neither seemed in the style of the owl to keep at hand. Toph, through struggling with her crutches through uneven footing, was happy enough being able to see there. After a time she announced, "There's something ahead." In a minute they came to a widened area bordered in slate stacked as walls. In a circular room they looked up and found the ceiling had opened wide and far above them, like being at the bottom of a deep man-made well. A staircase wrapped around it leading upwards. The top was boarded in wood but seemed constructed to open as a trap-door.

They looked to the firefly. It slowly began floating upwards. Jet hastened to scoop Toph up to carry and they ascended. Azula had gone first, and at the top found a keyhole and clicked the lock open, then pushed the wooden door up. It arced on hinges and toppled open with a dull thump. Brisk air thin and dry raced in, sending a chill down his spine. The firefly raised into the air unperterbed by the swift gusts tearing across and levitated unfaltering while they finished their climb.

Winter's cold bore down on them. They were at high altitude in snow-capped mountains, the sky above dark with night and traced in silver glitter of the Milky Way. With no light pollution it was apparent there could be no major settlement around. The stony ground was traced with frost and piled snow continuously being swept and replaced by the wind, which cut an intolerable bitterness that sapped his strength already and numbed his fingers. The deep well structure formed, at surface level, an old stone fountain which a sapling was growing out of—a yew tree—from the same root system as in the caves and in the cellar of the library. As they were left astonished in the new world they'd arrived to, the firefly descended again. A swirling tendril of root pulled the door closed after its passing.

He moved next to Katara and increased the intensity of his hand-held flame. It was hard to see anything through the snow and overcast. Having been an hour ago in the center of the former desert territory they seemed to have arrived at the other side of the world. Zuko was puzzled as the location didn't look like any place he'd ever been, and he'd been everywhere. No lights shone through the mountains or valleys and the atmosphere brewed thick, shortening his distance of visibility. He shivered involuntarily and clenched his jaw against his teeth chattering. They'd come unprepared for such temperatures and their thin desert clothing was insufficient.

I'll barbecue that owl, Agni help me, I'll make him into rotisserie. He raised the flame higher wishing for a bonfire. It felt like the night he'd taken his ship to the South Pole for the first time, the unfathomably bitter cold that gnawed at his bones with stunning intensity.

The mountain before them, which they were on a lesser peak of, had a strange silhouette unnatural. It looked like a tree with its upper branches lopped off by lightning or storm-wind and came to an abrupt summit with a few too many geometric shapes to be untouched by human hands, but neither could he discern any intact structure there. There were makings for such, but either it was unfinished or collapsed. His heart thudded with sudden realization that he had been there before, though at that time it had looked completely different. This was the Northern Air Temple, though something catastrophic must have occurred as most of the structure was destroyed. When he had come through while still banished and on the hunt for the Avatar, a small group of refugees led by an eccentric mechanic had been dwelling there in the ruins of the airbenders, but the entire temple had been wiped off the mountainside.

Wait. At that time the mechanist had mentioned they were having trouble with natural gas leaks. If the gas reserve had been large enough, could an explosion have caused this? It was only a few years ago. But in that case there's certainly no one living here now. Everything is gone.

Katara whispered, "Zuko, we need shelter. We'll die if we stay out here in this cold." She knew better than anyone the threats of hypothermia and frostbite.

"There might be part of the structure remaining we could shelter in, but what caused it to be destroyed the first time might still be dangerous to us. I don't know if it's safe to go over."

As they were discussing it, Jet gave a shout. He was still holding Toph, as, barefoot, it would be cruel to set her on the snowy ground, but he flicked his chin upwards. A large shape moved there approaching them. It was larger than any bird but, by silhouette, certainly was not a dragon. Six legs dangled above them, weightless in the air, before Appa landed and a bald young man in orange leapt from the reins. "Katara, Zuko!" Aang smiled ear to ear and hugged them in turn. "What are you doing here?"

"Aang?" Katara asked, "What are you doing out here?"

"I felt spiritual energy and came to investigate. The fire was easy to spot from the air." He had turned and seen Toph, her leg in a heavy cast, and his expression fell. He briefly greeted the other three and then said, "I'll take you inside. It's freezing out here." Appa was still saddled and they were conducted up with a gentle lift from airbending to catch a ride with him. They flew a brief stint to the ruins of the main structure. Much was blackened and toppled, but new construction efforts stood out obvious from their lack of char and damage. From the appearance they'd been made with earthbending and formed entirely of the present stone remains in the area, but the new structure was small in scale, the size of a generous cottage, though other failed attempts were scattered across the area.

Inside was blissfully warm and Aang had a hearth going to take the chill off. A special sliding barn door admitted Appa to a connected stable, where he nestled in hay enjoying residual warmth. The main living space had furnishings recovered from the ruined temple, including a table of wood splintered and weathered, a bookshelf, and a wooden trunk. Momo's soft shape was curled in sleep in a purpose-made bed for him, resembling a small crate packed with linen scraps for warmth, and he did not rise even as the group settled in. Appa as well was lethargic with the late hour. Aang pulled a kettle and began preparing tea for them at the hearth, saying, "I wish I had known you were coming. I only have one bed here, and it doesn't look like you have any supplies with you. How did you get here?"

Katara set Toph's crutches down next to her seat on a floor-cushion, then replied, "It's a long story, but for now let's call it spirit magic."

He sat down with them, the blue arrow at his forehead vibrant in the warm light of the shelter. "We have some time before the tea is brewed. It seems like I've missed a lot." With the kettle put on, he fished around for blankets and any spare clothing he could gather and passed them around. Most of the garments were in airbender colors, warm tones ironically reminiscent of fire and bright compared to the stone-bare, lofty peaks they had inhabited. Zuko shrugged on a large tunic with lopsided stitching, but which at least was in heavy linen, imagining it had been a failed attempt by Aang to make his own garments. After all, no storefront anymore sold such garments. The color splotched unevenly from home-dye by unmastered hands.

As she recounted the story for them, Zuko went to greet Appa, who nosed at him affectionately. He still had some extent of scarring and patches where the fur would not regrow, but seemed healthy otherwise. "Do you remember me?" The fondness in the brown eyes was answer enough.

Fragrance of pineneedle tea filled the space as the cups were poured out. Aang resettled, then began his own explanation. "Since I parted ways with you after we'd returned Song and Teo home and you two to the Fire Nation, I'd come back here to try to rebuild. I remember what the temple looked like, but rebuilding from memory hasn't been so easy. I tried drafting plans but they look like a child's drawings, not schematics, and haven't been useful. I was using earthbending but it isn't enough. There have been times I've made pillars or arches only for them to collapse again. The initial forms were precisely engineered, but I don't know how to recreate it. And I never realized, but the mountain itself is very much in motion and not inert rock. Small earthquakes barely enough to perceive can topple my structures or run cracks through their foundations. A mountain summit is inherently unstable ground. It's ironic, but to build an airtemple I think you need to be a master earthbender. I'm just not there yet."

"Have you been alone up here all this time?"

"Yeah, for about a year. I guess I don't have much to show for it." He paused to sip the tea then looked over to Azula. They regarded eachother wordlessly. It was hard to tell exactly what Aang felt about her, the woman who once deceived him and had him drugged and abducted into the hands of his enemies. While he didn't seem the type to hold a grudge, he wouldn't blame him for still being wary and a little bit resentful. Azula kept her face blank in the style politicians of their country used to hide their true intentions during negotiations. As she worked for the Earth King now, Aang wasn't her enemy, but there were likely bitter feelings as he'd been the fish to escape her hook and led to her downfall.

Aang had refrained from fussing over Toph's injury, but he glanced at her too many times with a look of concern for even her to miss, and she grew increasingly irate and began rapping her fingers on the table with a frown. She'd specifically asked them to not involve Aang but they'd encountered each other anyway through the enigmatic machinations of the spirits. Zuko and Katara had left out any explanation for why she was there with them to begin with, an obvious hole in the story which Aang had certainly noticed but politely declined to comment on, but that only left it unstated for the time being.

As Aang was telling them tales from when the temple had been populated, during his childhood but a century ago for the rest of the world, Toph huffed and shifted miserably. Finally, her patience at its limits, she shouted, "We didn't come here for a history lesson! To stop the merchants we need to find an army and take them back with us through that tunnel." Everyone paused and averted their eyes. She was upset to the verge of tears, and it expressed as unreasonable anger at Aang, who was only patient and polite in return. This was intolerable to her, and she continued berating him, "While you've been up here playing house and knitting sweaters I was busy trying to put a stop to those bastards, and you're just sitting around in a little paradise of your own like a recluse. Some Avatar you are! You haven't done a thing for anyone. You haven't helped us." Her voice broke and she wiped roughly at her cheeks sniffling, her nose red from cold and emotion alike. "So I don't want to hear about your stupid air nomad stories and your temples and meditation sessions. I want to go back there and finish what I started, and I don't have time for this."

He waited patiently for her to calm down, his expression soft, and she swore and shifted her cast leg with a painful expression. They hadn't brought her medication and it was likely her pain was returning without the solution of the flower to dull it, and it was doubtful that Aang had any medical supplies of use. When she was quiet, he replied, "I'm not an army, but I might be able to help."

"I don't want your help," she retorted. "I want real soldiers, not someone content to sit around all alone digging at ruins."

Unoffended, he stood to fetch an item from the bed and then returned to the table. "Well, I haven't just been doing nothing. Here." He lifted the item to his lips—a polished wooden flute—and a note rang melodic and crisp. She paused in her rant and listened as he continued through a melody, intricate and difficult in execution but conducted flawlessly. Momo shifted and resettled with an accompanying trill that faded to resumed slumber. Aang's fingers shifted over the holes to guide each note with easy mastery, like he'd practiced that song a thousand times. Toph's expression was surprise, and it was obvious she recognized whatever was being played. She held her hands in her lap and closed her eyes, listening intently with her eyebrows knitted, until he finished. The last notes played out pure and lingering, then the silence of the dwelling after felt desolate by contrast.

He waited for her judgement. She said softly, "That's the song I mentioned to you."

Aang smiled. "I learned it for you."

She'd stopped crying. Instead, she said, "I'm tired," without any of her prior bitterness.

"You can have my bed. In the morning we can figure out a solution, okay?"

He went around to help her up and guided her to the narrow cot. Finished their tea, the rest of them settled where they could find. The fireplace continued burning through the night with the brightness of pinesap and mountain grass, casting a gentle flicker through the warm interior. Aang, content himself to sleep sitting up, leaned against the wall by the hearth, toying with the flute as if nostalgic while the others fell asleep.

#

Katara awoke with Zuko still at her side, though it was mid-morning and he must have been up several hours. His eyes were open and he was staring at the ceiling in thought. She shifted and he looked over and said, "Good morning."

"You could have gotten up."

"It's cold out. I would rather be here with you," he whispered. They were settled with hay softening the ground and a blanket above it, tight beside each other sharing another. Appa was gone, as were Azula, Aang, and Toph. Momo, though, was curled on Jet's belly asleep. He was sound asleep in his own makeshift bed and looked peaceful for once without the depressive shroud the alcohol brought. "Aang left breakfast for us. Just rice and pickled vegetables. He mentioned there are rivers in the valley we could fish in later."

She was concerned for his health. If he'd been up there a year in isolation with no community around, she wondered what he had been eating, especially after frostfall when agriculture was finished for the season. They moved together taking the entire blanket with them to the table where the ricepot was covered and wrapped in fabric to retain warmth. Zuko heated leftover tea for them and they breakfasted quietly with Jet's soft breathing in the background. He must be tired. Maybe the mountain's cold air helped his insomnia.

Finished their meal, they tried to rouse energy to confront the cold outside. She ran her fingers through her hair—they'd left all their luggage behind and she didn't even have a hairbrush, and Aang certainly didn't—with the blanket over her shoulders. Zuko finished tying on what clothing he could find and they slipped out the door quickly, trying to keep the heat in. She pulled the blanket around herself and shivered. "It feels like home." When she said that word anymore she had a double vision of Caldera City and the South Pole.

He breathed deeply and exhaled, warming himself with his internal fire. She envied him then—such a technique would have meant the difference of life and death in the South Pole. The sky was crisp-blue and air light from altitude. They'd been the previous day at sealevel in the oasis city Shambhala and the adjustment was difficult for anyone to transition so rapidly. Zuko said, "Don't exert yourself too much. It's easier to get lightheaded up here."

She huffed and went to look around. Toppled columns of new stone crossed the blackened rubble of old. Aang had not exaggerated his efforts—the temple's campus was littered in his attempts both to clean-up and to reconstruct. Traces of strange machinery were scattered and she knelt to pick up a screw of corroded metal. He continued, "You should have seen it before it was destroyed. The machinist's group had pierced the temple through with experimental machinery—Aang would have had an anneurism if he'd seen the extent. They'd all but destroyed the temple as the air nomads had left it."

"They were up here by themselves coming up with all that? What was the purpose?"

He kicked at the snow settled between stones. "They were making weapons for my father. I don't have the heart to tell Aang, but he might have found out by now if anything had been left of the equipment. The remains of the temples are all he has left, so I didn't want to ruin their memory for him. In a way, it's good this place was destroyed. By the time the explosions went off there wasn't any unadulterated section of the temple remaining. Well, except for that well. It was so far from the central part it must have fallen outside their plans, especially as it appears to be dry."

"Did Teo know?"

"When this happened, he must have only been fifteen or sixteen. His father might have kept him in the dark. Regardless, it doesn't make a difference now. I'm sure you've figured out why the owl sent us here."

"Aang—the Avatar. He's the 'army' we need. Unfortunately that means we need to explain what's been going on."

"He's not a child anymore."

"He was a child when I found him." She shrugged the blanket tighter and kept exploring, wondering where they and Appa had gone. "Do you think he's eating enough?"

"Well, he seems to be growing tall enough, so probably. The real question is what is Toph doing to him right now."

The mountaintops were uniform snow in the depth of winter, but the valleys were lofted in pine. Any wildlife in the area would have descended for the season and, at the height of the temple, nothing stirred at all. She paced through collapse and partially-intact halls, interiors missing a roof's shelter and covered in snow blowing against doorways cluttered by rubble. At one end of the mountaintop a deep crevice with crumbling edges cleaved the mountain apart. Zuko put a hand on her shoulder and held her back. "This is the origin of the explosion. If I were to light a fire here, the gas deposit would ignite. I hope my sister isn't off holding a practice drill. If she died right after sucking up that oasis water I would curse her