Some part of Iron Quill hoped that some of what the Polestar had done had made him magically immune to the cold. But as he returned to the colony beside the exhausted princess, he was disappointed. The air still caught in his chest with his first breath, sucking what little of his strength was left and assaulting him like a physical force.

As he entered the cave, he stopped for a moment to appreciate Nightmare Moon’s work. A gigantic metal spike pierced the ceiling now, almost directly overhead. It didn’t make it quite to the cave floor, but close. There on the far side of the cave was the shelter he had ordered, with everypony except those cleaning the air tucked away in a tiny area for sharing warmth.

He didn’t go to the warmth, but straight to his own camp. He tried to fly, but the ice bit into his wings so quickly that he had to land, tucking them under his robe and tightening his scarf about his face. The frost he exhaled didn’t even float away anymore, but straight down to join a surprisingly thick layer of moisture on most of the cave floor. How cold can it get up here? Nightmare Moon had said, when they first arrived: colder than the void.

He stopped outside his tent, where many of the gawking crowd was looking and pointing. Nightmare Moon had done nothing—either too exhausted from the effort, or content to let him take credit. Whichever, he wouldn’t waste it. Did he still have the strength to yell like a soldier?

Yes, as it turned out.

“Ponies of the Lunar Army, and those trapped with us!” He shook free of his robe, spreading his wings again. He could hover for a few seconds; he had enough warmth for that. That way the ponies would be able to see him, even with the slope. “This is not an attack, or any reason to fear. My engineers have designed a method to prevent this cold from returning!

“We have some work to do if we wish to survive the next cold. Our princess has provided the most important part. The rest will fall to us, the product of hard work and cooperation. For now, return to the shelter and pass the message on. This is the last time we will face this cold. When the sun returns, it will take the ice away for good!”

For the first time since Quill had become Lord Commander, he heard cheers. Uproarious shouts began at the center of the crowd, then spread backward. Soon the whole cave seemed to be shaking with their voices. Quill hovered there for another moment more, so they would all see him. This was his promise, and each promise he kept meant an easier time winning their support.

Then he landed, turning back to his command tent. He could only hope that it was still being heated.

The command tent had been covered with several layers of thick cloth, several interlocking sections of other tents and scavenged blankets. Before he could find the entrance, a pony nudged him from behind.

“You went with the princess to Vanaheimr and came back,” she said, impressed. “Aminon said she was taking you there to sacrifice you to the spell that killed us.”

“Penumbra.” He turned slowly—everything he did in this awful cold was slow—and for the second time he stopped dead to stare.

Penumbra had a shadow too, stretching towards the light instead of away from it. There were the same red eyes peeking out, the eyes Quill knew well. How had he spent years with these ponies without noticing? He didn’t wait long though; it wasn’t as though she’d done anything. “We did try to get through the defenses. There’s…” How much did Nightmare Moon want him to say? She’d been harsher about the contents of that room than anything else since the rebellion began.

“There was a hope that we could’ve returned to Equestria. But it didn’t open for me.” Because I begged it not to.

“That’s what that smell is.” She circled around him, sniffing and turning up her nose. “Smells like it burned you. But you don’t feel injured. I’d have sensed that before I left your tent.”

It did something all right. Quill couldn’t imagine an actual use for seeing shadows, but maybe if it made him smell bad to Voidseekers, that was enough of a purpose right there. Except for with Penumbra.

“I’m glad it left more of you alive,” she went on, sounding almost casual. It was a little forced as she rested against him, silent. Her whole body was icy cold, but he didn’t mind. “The others… three died wandering the outskirts of that place. It smells like you walked right up to it and came back.”

I don’t think it likes demons very much. “I’m glad too. But… we still have to survive this frozen nightmare for ten more days. I didn’t think it could get any colder, but… is it warmer in there?”

She shrugged. “Maybe. Your friends are burning charcoal. Look up.” She pointed, to a hole in the top of the tent, and a trail of smoke trickling upward.

Quill stood beside her another moment longer. “I’m glad you’re okay,” he whispered. “I thought Aminon might… he didn’t seem…”

She chuckled, pushing him gently away with a wing. “Aminon can’t hurt me. We serve the same master. You, though… if you keep refusing Nightmare’s promises, he’s going to find a way to kill you.”

“I assume you… don’t have to listen to him if he demands you do it?” he asked nervously. “I’ve grown comfortable trusting you.”

Penumbra froze for a moment, her expression a mask. Was Quill imagining it, or did the shadow stretching towards the tent glowstones no longer seem so dark? “Not him,” she said. “It’s the princess you must appease, Quill. If she orders it, I must obey her.”

“She won’t,” he said, hoping it was true. “Nightmare Moon doesn’t want to herd cats. Even when the army is suffering, she always let captains settle matters amongst themselves. She would let Permafrost kill me…” There was an implication buried in that, just below the surface. She’d let Permafrost try to kill him. That probably meant she would let Aminon do the same.

He wanted everyone to swear to Nightmare and kill the rest. The closer I get this army to stability and safety, the further from his goal we are.

“Can I…” He hesitated. “Ask you to help me if Aminon comes?”

She met his eyes, silent for a long moment. She was so close, close enough that he might’ve wanted to do something else. Except that he was frozen and wrapped up in so many layers that he couldn’t escape even if he wanted to.

“I can’t stop him,” she whispered. “I’m a better fighter, but he knows Nightmare like none of us do. He would make Permafrost’s dueling look like a foal learning to walk.”

“Warn me,” Quill begged, not letting her look away. “That’s all I ask.”

It looked for a moment like she was suddenly frozen—but then she nodded her head, just once.

“Are you two gonna kiss or what?” Cozen asked, poking her head out of the tent. “Your adorable little inventory pony is having a nervous breakdown in here waiting for you. Come in before her heart gives out.”

“It would not!” a pony’s voice snapped, though she hardly sounded very confident. Silver Needle was in there.

Besides, he was freezing his flank off. Quill turned away, ears flattening in his hood as he went for the opening. Penumbra followed, and the two of them stepped into the tent. As soon as they were through, Cozen began carefully overlapping the cloth again, sealing the freezing outside away.

The heat inside was almost as much a physical force as the cold of the cavern. Iron Quill removed his hood, unwrapping his face. Everypony inside the tent was still wearing their jackets and cloaks, so he left his on as well, even if the warmth was oppressive.

His three most-trusted advisors were all here, though Sylvan Shade was the first to speak. “She actually did it? How did she find the metal so fast?” He nudged the metal lump Penumbra had found with one hoof—from the way it sat near the end of the table, Quill guessed it wasn’t warm anymore. “That should’ve been… days of flying, maybe.”

How much could he say? “We found one big piece,” Quill said, removing his saddlebags and hanging them in their usual place. He thought about showing them the artifact he had brought but dismissed it for now. They could investigate the strange and unknowable creations of Vanaheimr when they weren’t freezing to death. “Never mind that—she did what you asked, all at once. Metal is installed, and as you can see we still have our air.”

“The power of an Alicorn,” Sylvan whispered, awed. “You see them walking around, and you forget they have the strength to move the sun. We need to work our local goddess into our calculations more often.”

“I wouldn’t.” Penumbra sat down on an empty cushion on the far side from everypony else. “Her patience is limited, and it seems like Quill spent much of it. It might be some time before she helps again.”

You didn’t see her in the ruins. Luna is in there somewhere, no matter how powerful Nightmare is. Luna wouldn’t leave her friends and supporters to die. “I want a report,” Quill said, severing this line of reasoning before it could waste time. “What happened while I was gone?”

“Two more dead,” Silver Needle said, interrupting. “One from outside camp, one a still-recovering soldier from Motherlode Company. I ordered them stripped and interred in the crypt-cavern with the others.”

Quill nodded. “There will be other consequences of these next ten days, even if the majority of our army survives. Frostbite leaves deep scars, and we have no unicorn healers.”

“One,” Cozen corrected. “She’s in your new company, Lord Commander. Marine Kelp is an adroit enchantress—but she is fiercely loyal to the Ordo Celestial and would probably poison any of your soldiers you sent to her.”

“And you just…” Penumbra stared openly. “You just told me we have a heretic hiding among our soldiers? Why do you do things like this?”

“Because I’ve learned you aren’t a homicidal maniac like Voidseekers are supposed to be,” Cozen snapped. “You’re sitting at this table and helping us save Luna’s army. What do you care who they pray to?”

Penumbra had no answer to that. In the light of a modest charcoal-burner, her shadow seemed to fade almost completely. She looked confused—almost the exact expression Quill had seen on Nightmare’s face after visiting the Polestar.

“Regardless.” Quill smacked one hoof on the table. “Needle, finish your report.”

The shy unicorn smiled gratefully before continuing on. “Shelter strategy seems to be working. If you visit, you’ll find it’s much warmer than this tent. I’ve rationed all our oil to last through these ten days. So far, soldiers seem to prefer giving up personal space to freezing to death. We’re still fine-tuning the timing of opening the bottom of the shelter to exchange air with the cavern. Oh—our treatment pits have frozen solid, so the ponies aren’t working those anymore.”

“Unfortunate, but… we lasted more than ten days before dying last time.” Quill turned to the others. “You can stop the oxygen-machines as well.”

“We did,” Sylvan said, without annoyance. “And drained them of water to avoid shattering the mechanisms. We want it broken even less than you do, Lord Commander.”

He raised a wing in surrender. “Apologizes, Sylvan. I shouldn’t assume… You’ve seen the way this army acts sometimes. I’m not used to predicting intelligence.”

Cozen rolled her eyes. “Let’s skip past all that and to the important parts. We did it, Quill. If the length of time before we ran out of air holds, we’re going to make it. We can stop worrying about freezing to death this time and concentrate on how we’re going to build an entire underground castle in a month.”

“We, uh…” Silver Needle squeaked, then straightened. “Tests are complete on the room sections. It’s exactly as I suggested, of course. The double-insulated room stays warmer for longer. It doesn’t produce heat, obviously, but…”

Quill nodded. “Then we can appease the idiots and fools. What about my other instructions?”

“We’re saving everything,” Silver Needle said. “Everything, just like you asked. Right down to the campfire ash and latrine pits.”

Penumbra burst out laughing. She slumped forward, unable to hold herself upright. “You’re… bucking joking. You told them to save the contents of latrine pits?”

Quill nodded without shame. “I did. And burned firewood, and scrap cloth, and literally anything else that we use or dispose of. Even the dead will be safely stored in the crypt.” He met her eyes without blinking, or any shame at her laughter. “I know how to manage an army, Penumbra. A large part of keeping a force like ours fed and supplied is managing profit from raids with expenses to merchants. If you’ll notice, there are neither here. We cannot requisition food from villages we visit, we cannot raid hostile cities for gold. We cannot trade with merchants. What you see in this camp is all we have.”

He lowered his voice, barely above a whisper. “It may be all we have for our entire lifetimes. We must survive on what we brought, and what we can build. That is all we have.”

Penumbra stopped laughing. He couldn’t see her face, but he guessed she was probably still amused by everything. Whatever, he didn’t mind.

“I think these ponies are tired of living in tents,” he went on. “An army can only remain deployed for so long before they become frustrated with the experience. Perhaps they don’t want to live so close together—but we can tell them that the choice is that or keeping their tent when it gets cold again. See what they pick.”

Quill removed the tightly packed scroll, the one he’d used to show Nightmare Moon their plans. He spread it on the table, covering all the other manifests and casualty reports and everything else. “We need to look ahead. We have half a month of warmth before the sun departs again. I want construction plans to build the most critical sections first. Plan for the absolute minimum amount of space to safely hold every pony in every camp. And the followers as well. We’ll want to house them separately eventually, but for now it’s just about survival. We can…”

There was a plan forming now, a solution to his growing fears about their failing gold supply. “For the short term, we will let them lease space in our cold shelter. Camps too.”

Cozen whistled. “Pay labor companies to help the army build a fortress, they make them pay you to use it? They won’t like that.”

He nodded gravely. “I’m sure they’ll be furious. But…” He stood up, meeting her eyes. “We. Won’t. Tell. Them. Until. They. Finish. Are we clear?”

He expected argument, but she didn’t offer any, just nodding curtly.

“And let me be clear.” He leaned closer, folding his wings. “Nopony outside this tent knows. Penumbra would die before violating my orders, Shade works for the army, and I would trust Silver with my life. If they come to me, I’ll know which of us betrayed my trust.”

Apparently he’d guessed right about her intentions, because Cozen rose from her chair, glaring furiously at him. “It’s wrong! Everypony deserves a safe place! They shouldn’t have to pay for it!”

“They shouldn’t,” he agreed, exasperated. “But right now, we don’t have a choice. Everypony still expects their bits to have value, and that’s part of the reason we’re still able to get things done. Let me remind you, Cozen. I have all the food. For every mercenary outside the camp, I have ten veterans. I have captains calling for the outsiders to be marched out to the surface and left to die.”

He slumped back to his chair, lowering his voice to something calmer. “Look, Cozen. I promise not to let them die. Anyone who can’t pay, I’ll find a way to get them in. But we don’t have the luxuries we had back in Equestria. They can’t choose to leave; they can’t forget about food and eat grass. They can’t switch sides.

“All of us have to work together. That’s why I built a new company from those ponies, a company of laborers and magicians instead of soldiers.”

“And whores,” she snapped. “You could just call them what everypony else does.”

“No. The builders and mages are still builders and mages. But the whores are something better now. I won’t call them by what they were. And you will remember that I’m the reason they aren’t frozen and suffocated out on the surface. You will remember that I intend to save everypony here, including them. Is that clear?”

She met his eyes for another moment more, then nodded. “Yes, Quill.”

He didn’t push her on the name this time, just turned back to Silver Needle. “As I was saying—I want a work schedule for the most critical parts.”

“How many hooves?” she asked, removing a scroll and a quill from somewhere and glancing at the blueprint. “All two hundred fifty, I assume?”

“No.” He shook his head once. “How many hooves still live, in the whole army?”

“Two thousand, eight hundred… something,” Silver Needle said.

“And of our followers…” He did some quick addition. “Work orders for four thousand stallions and mares. When the sun returns, and the cavern warms again, we will make new orders. We won’t be selling food to anypony able-bodied in the army or out. If they want to eat, they work. Make sure you allocate enough supervisory positions for their officers not to feel insulted. But they’ll be working too.”

“Seems like you’re determined to make the army hate you again,” Penumbra muttered.

He shrugged. “I’m not so sure. Soldiers might complain about working, but most of them hate sitting around more. You can only play so many hooves of cards and drink so much wine before you’re ready to get out and work. Or kill, but we don’t have any enemies to fight up here. So work it is.”

They had to survive first. The moon didn’t make that easy on them, not with the cold getting worse every day and ten awful days to survive. After three days it became basically impossible to leave the shelter, even for the strongest and best protected. Only the Voidseekers were immune, though there was little for them to do.

They packed in tighter, rotating ponies from front to back in the cavern to take turns against the blistering entrance. What physical conflicts there were—or fights between soldiers and camp followers—those all came to a halt by the fifth day. Ponies were just too cold to fight.

There was only so much oil, for their sparse fires. They burned them at the cavern-end, where they could be most rapidly exchanged with the larger supply of air, and where they would help keep off the worst of the chill. But they didn’t have anything near enough.

At the end, even Nightmare Moon entered the cavern, striding through the entrance with her entourage of Voidseekers.

Quill was there, guarding the place their oil supply had been with Chain Mail and a few other loyal stallions. There was no oil anymore, no fire. Just the frost that coated everything, and the air that pressed down on them with the weight of icy blocks.

He had the strength to rise for the princess—not everypony did.

“This is what became of my army?” she asked, looking down the tunnel. “I expected more of you, Quill.”

There were no longer camps anymore, just ponies huddled together as close as they could under what blankets they could find. There were no more camp kitchens, no more sparring circle or library. Nopony played their instruments anymore. They just cowered.

“They live,” he answered, not meeting her eyes. “Mostly. We lost a dozen ponies last night. Six before that, four the night before—”

“I hear you,” Nightmare Moon said, silencing him. “What would you have done if the night was twice as long?”

“Die,” he said.

She didn’t laugh, but one of the Voidseekers behind her did.

“That does not serve me.” Her horn began to glow. Her shadow reached towards the flames, more subdued than usual. It still watched him. “Even when the sun returns, it will take time to heat the cavern through our thermal conduit. Without the rest of the system you designed, there will be no way to regulate it.”

“I know,” he croaked. “We, uh… work schedule…” His head swam. “There’s a method. We will… get the reservoir built first… something something… ice… water…”

“You’re dying too,” she whispered. “I suppose I shouldn’t be surprised. But it won’t serve.” She looked up, staring straight out at nothing. “I cannot warm what is frozen. But the moon is mine to command.” Energy stretched from her, scorching the walls, and causing ponies to retreat in fear. Even her Voidseekers backed away. “This night is ended!”

Quill’s hooves froze to the cavern surface, as energies he couldn’t even imagine gripped the moon along its axis and twisted as only the Princess of the Moon could command. Whatever Celestia’s curse, it didn’t stop her.

Nightmare Moon landed roughly on the cavern floor, sagging visibly. “N-now…” She turned. “Voidseekers… back to… the throne room.” She glanced over her shoulder, meeting Quill’s eyes. She said nothing, but he imagined he could feel her reproach. You thought I would leave you to die?

In that moment, he knew Luna was still in there, somewhere.

Even without a single window to the surface, Iron Quill knew Nightmare Moon’s command was obeyed. Over the next few terrible hours, the cavern began to warm. They felt it from the entrance first, spreading downward towards the larger cavern.

Quill wasn’t sure how long he slept. Days, probably—there was no one strong enough to turn the hourglass for something as insignificant as tracking hours. But eventually he woke to the sound of music from down the cavern.

Somepony had a lute and was playing a simple hymn. One of the old songs, written before the rebellion. A song of thanks for the mercy of the night, and its time of rest. Quill listened in silence until the song was done. Then he rose, shaking once at the moisture on his clothes.

Moisture, not ice.

He wept.

Then he stumbled back into the main cavern, with a sizeable crowd of ponies just behind him. They were no longer separated by company—they were all survivors now, of the moon’s terrible wrath.

It was still too cold to return to the main cavern—the huge metal mass took more than a single day to heat, and the cave was deep. But the shelter was warm enough that nopony died that night. They left just once—to hold a memorial for the over a hundred dead. The oldest, the sickest, and the young.

“Tomorrow we will return to work,” Quill said, when the service was complete, and the dead had been carried away to the crypt-tunnel. “The terrible cold will return. If we aren’t prepared for it, we will all die. Every set of strong hooves must take up their tools and labor together.”

He hopped up onto the raised wooden platform, pointing at the huge metal spike above him. Water dripped from it almost continuously now, forming a growing pool underneath. He stayed out of the flow. “With your hard work, and the Princess of the Moon ruling over us, we cannot fail. We will survive.”

Nightmare Moon rose from her throne at the end of the platform, stalking forward towards him. Quill bowed, and so did most of the army. She stopped at the edge of the stage, looking out at everypony.

“I always believed the strongest ponies served the night, but now I know it. Many hardships wait for us—but they make you stronger. At the end of all your pain waits our revenge. We will return to Equestria and take back what was stolen from us. I will return your suffering a hundredfold on the loyalists and petty tyrants of Equestria.”

The crowd cheered.