It was only reasonable to set up a makeshift camp right in the library, settling in for an extended period of study and exploration. The ancient facility was expansive. Constantly moving between their original quarters and this archive on a daily basis just wasn't reasonable. Especially as they could designate any hall as a kitchen and any smaller rooms as their bedrooms. The original assignment of the spaces meant little centuries after they were sketched by the architects.

During the day, Lila would go out to hunt, gather food, and check the security perimeter while Aira stayed behind to read and learn. The books were dense and filled with technical jargon. The language was similar to what Aira learned in the past months from Lila, but the centuries that passed since the books were written had changed it. Sometimes, it was easy to recognize the old words and meanings. However, in other cases, Aria had to cross-reference the unknown terms between different manuals and workbooks. In the end, it was thanks to Aira's sharp mind and her high intelligence stat that she started to comprehend the new knowledge and even implement it in minute ways.

She dove deep into the technical manuals, absorbing information about various energy sources used in the Old World. There were sections on fossil fuels, nuclear energy, hydroelectric power, and more. However, as Lila explained earlier, many of these techniques were either impractical or impossible in their current situation.

All these new concepts overwhelmed Aira. In her world, all of that either wasn't common knowledge or was a part of some branch of magic. It was like studying the universal laws all over again.

Time passed, and one day gradually turned into another. Especially as for Aira there was little of a difference between nights and daytime. It was always library time for her. Their camp was now cozy and homey, thanks to Lila's efforts. Aira immensely enjoyed the simple meals her companion cooked from the stuff she hunted and gathered. Especially when the human brought her treats directly to the archive.

"Ah, yes," Aira thought on one of these occasions. "My tutors would be mad if they saw this violation of library rules."

Still, not to rely exclusively on this one source of energy, Aira made a point of venturing outside with Lila from time to time to boost her reserves. Not too much, though, as there was so much stuff to explore within the pages of the ancient books and documents.

One of these evenings, while flipping through an exceptionally detailed manual, she found information about something that could save them from their fuel troubles: something the ancients called 'sustainable energy.' Specifically, two types of power generators should fit the bill if they were able to find the needed parts in the storage rooms.

All these concepts were absolutely foreign to Aira with her habit of using magic. In this world, people were able to replace the arcane powers with science and technology. But even then, the System dawned on them, and what...? their civilization was ruined by the rift between the humans and the undead.

In Aira's world, the introduction of the System happened eons ago. Even myths about this age haven't survived the time. But now she was getting a glimpse of what it could have looked like: fear, chaos, and uncertainty in the next day.

Aira was astonished by the achievements of the ancient humans and the detailed information provided in all the manuals she found in the library. Even a child should have been able to recreate the technologies explained there. Given they had the needed parts, resources, and time.

The manual Aira was researching right now explained the magic... no, the technology of 'solar panels' converting sunlight into 'electricity' and described the turbines that used the power of wind, both providing a renewable and reliable power source. Aira's excitement grew as she realized this could be their solution. So, when Lila returned, Aira eagerly shared her findings.

After spending at least half an hour reading Aira's notes, Lila nodded, her expression thoughtful. "By the Elders' breath, I swear I've seen those somewhere before! One of these storage rooms has them stashed, but this place has more twists than an old oak's roots. I just need to remember which one. There are so many of them here! Fingers crossed those panels still work after all these winters."

Of course, it took some time to retrace their steps, locate the right storage hall, and sort through all the boxes and crates placed there by the ancients. But their persistence paid off. Lila was right. There was a stock of solar panels there. What was even more exciting, judging by their appearance, was that they were still in good condition despite their venerable age.

***

By then, Aira and Lila had been working together for over two months. Their partnership started with curiosity, some degree of mutual mistrust, and, if you'd ask them to be totally honest, a bit of fear. The challenges they went through together had varying effects on that relationship. There were moments when it improved, but there were also setbacks. Ultimately, both women focused on building a friendship based on mutual respect and a shared determination to unlock the secrets of the world that surrounded them.

On one of the mornings, during breakfast, Lila mused: "You know, it's kinda cute how I'm picking up your growls like they're plain as a mountain stream. Who'd have thought those roars could hold more meaning than an Elder's briefing? I'm sure none of my fellow humans ever considered that it is a form of speech!"

Aira growled cheerfully in response.

"But that way of communication must be frustrating for you," Lila continued. "Using these journals I found for you to scribble everything down feels slower than moving through mud, even with your... hm... magical shortcuts. We've got to find a better fix for this. Maybe with your special skills?"

Aira nodded. She was as frustrated as Lila, having to spend so much time transferring through writing some of the more complex technical concepts from the books she's been reading recently. They needed a better solution for communication. One that didn't rely on her crude vocal capabilities of an undead or the tedious process of making tons of notes.

She grabbed her journal and wrote: "Remember I asked to try something with you just when we escaped Mountain View? I really hoped it would work and I should have done exactly that, simplify our communication. Alas, it doesn't seem to be possible. And I don't know what else I can do if you can't access magical abilities."

"Yeah... But isn't it bizarre that there is magic in this world but we, humans, aren't allowed to use it?" Lila asked. "What is the reason for that? Did the undead snag all the good stuff? And if yes, then why such an imbalance exists? Why?"

Aira shrugged. She didn't have answers to these questions. She'd be happy to find them, though, as this information may help her in her quest. But that was a concern for the future, not for today.

If you discover this tale on Amazon, be aware that it has been unlawfully taken from Royal Road. Please report it.

She truly hoped that once they had a stable energy source, they would find or create a device to bridge the communication gap more efficiently. But for now, they focused on harnessing solar energy to power the facility. And there wasn't enough time to explore anything else.

After a few days of deliberation and exploring the outer halls of the ancient building, they decided to set up the solar panels on the facility's roof. It was the safest location and the place with the highest light availability. The addition of the new objects shouldn't be too conspicuous. They shouldn't be seen from the ground level at all. And even if someone noticed the change, reaching the roof would be challenging after Aira and Lila blocked off most of the stairways and passages that led there.

The downside was precisely that: stairways. A multitude of them. The building was sprawling and occupied a fair part of the valley. But its vertical spread was even more impressive. So, they had to drag all of the needed equipment from the lowest levels where it was stored to the roof. It was hard labor, but at least Aira's strength and endurance stats weren't as stunted as her agility. So, she was able to carry a bit more than Lila. And with constant boosts thanks to her advancing mastery of the Energy Manipulation skill, she made twice as many round trips as Lila without even needing to take rest breaks.

***

The first time they went out on the roof, Aira gasped in surprise. The land around them was completely white and covered in snow.

"By the roots, time's been sprinting like a fox!" Lila said. "When we first crossed paths, it was all autumn leaves. Now look at this white blanket—it's winter already! Maybe you'd notice if you weren't always buried in books. Ever think about stepping out and catching a leaf now and then?"

With such a large construction project at hand, they now measured time not even in days but weeks. Installation of the first solar panels on the facility's roof took a lot of work. The panels were large and cumbersome, and securing them to the deteriorating structure was physically demanding and mentally exhausting. Moreover, they wanted to avoid risking damaging the ancient tech. They checked every step not even twice but thrice, ensuring everything was done up to the standards of the old books.

Aira used her Energy Manipulation skill sparingly, careful not to drain herself as she had done before. Still, it was easier for her to tap into the ambient energies in the open space as she could feel the power emanating from nearby trees and plants surrounding the building and growing all over it.

Despite the hard labor, Aira once again felt like she was full of energy. First time after opening that damned door.

Lila was also invaluable during this process. Her knowledge of basic mechanics and engineering came in handy as they navigated the complexities of the installation. She climbed the rusted ladders and crawled across the decaying roof with the agility and confidence of a seasoned ranger, ensuring that each panel was securely fastened and properly inclined to capture the maximum amount of sunlight. Not that rangers were specifically trained to do that kind of work.

The solar panels gleamed in the morning sun, their sleek surfaces starkly contrasted with the aged and weathered building. It was surprising how well they were preserved. Probably, one of the reasons was that they weren't under the influence of the elements all this time. Or was it the quality of storage? It was hard to tell without knowing more about the ancient human civilization. But Aira was curious if there were more occult reasons for that durability.

As they carefully maneuvered the cumbersome panels into place, the creaking of rusted metal and the crunch of debris underfoot echoed around them. The air was crisp and cold, and each breath seemed to crystallize in the frosty morning air. Every morning, they started with a brief patrol of the valley to ensure there were no rangers lurking nearby. But even during the day, they preferred to be cautious and not attract too much attention.

Once all the panels were in place, they began the painstaking task of laying the power lines down to the enormous battery packs they had found in one of the storage rooms. These batteries were much larger than anything Lila had seen before, their size and capacity a testament to the advanced technology of the Old World. Aira tested each of them by pouring a fraction of her reserves into them. And... they worked! The charge held, and Lila was even able to connect some of their simpler gadgets and transfer some juice into them.

While Aira sensed ancient power lines within the walls when they first explored the building, it took a lot of work to tell how well they survived the time. And during the first days of mapping, it wasn't their focus anyway. So now, the plan was to make temporary connections and then check the hidden conduits. Using them was the final goal, as it should make the setup less inconspicuous in case anyone decided to check the facility and could open some additional paths for further exploration and extended use of the ancient building.

"We're on the downhill roll now—just a few more lines, and we'll light this place up," Lila said, wiping sweat from her brow as she secured another connection. "Who knew all my ranger training would end with me tangled in wires like a squirrel's stash?"

Aira nodded, her excitement building despite her exhaustion. She growled with a smile, which Lila recognized as, "Can't wait!"

She grinned back. "Me neither. As clear as noon, this is going to turn things around for good!"

***

That evening, after a day of intense labor, Aira and Lila had a celebratory dinner. And there was a good reason to be cheerful: they had made the last connection just an hour earlier. Their solar farm was ready to supply energy to the batteries they had arranged in advance in the bunker.

The meal was simple, only the things the forest provided them with. They didn't have any trade with the human settlements as they feared retribution for what they had done in Mountain View. Moreover, they'd prefer if their location and the changes they made at the ancient facility would stay secret. Still, Lila and Aira have outdone themselves in preparing the food.

"It was truly beautiful, when we stood in the last evening rays of the sun on the roof," wrote Aira. "The solar panels looked like magical objects on the top of this forsaken building!"

"By the Elders' breath, that view could make anyone feel small," Lila said, a touch of awe in her voice. "Even when my grandfather brought me here, he never thought climbing to the roof was worth the effort. But that's his loss, I guess."

She drank some tea and then continued. "I can't wait to test the system we assembled," she said. "If it works, I'll feel as steady as pine bark leaving this place for longer stretches."

"That's true," wrote Aira. "And I have to explore, I need to find more information and continue with my quest!"

"Ah, that..." said Lila. "How do you even plan to accomplish it when you don't know what are the tasks you need to fulfill?"

"That's a good question and I don't have an answer to it," wrote Aira. "But if we don't do anything, I for sure wouldn't be able to complete it."

She took another piece of paper and wrote. "By the way, talking about time spent together. And I hope you don't mind me asking. I have never seen you dyeing your hair. How do you keep the color without magic?"

"Huh? What do you mean?" asked Lila. "How do you keep your ginger color?"

"I was born with it!" wrote Aira.

"What, my green hair?" Lila asked, amused. "Had it since I was a sapling! Don't folks in your world grow shades like this? Or are they stuck with plain browns and blacks?"

"No, they don't grow anything like that," wrote Aira. "And no, they aren't stuck with only browns and blacks, as you can see on my example. But I've noticed some other rather unusual shades while I stayed in Mountain View. I guess that's just a peculiarity of your world. Before, I could make my hair green. But I had to use magic for that. Sorry for offending you."

"No offense taken," said Lila, laughing. She stretched her arms wide and let out a long yawn. "It was just a bit unexpected. Anyway, it was a long day, and we can't test the system before morning. I'm going to sleep. What's your plan—staring at the stars like a moon-blind wanderer?"

"Ha-ha! Right, I don't have any research to do at the moment," wrote Aira and smiled. "I'll probably meditate and train. You joke, but maybe I'll go to the top and enjoy the view. Stars and moons are visible and bright tonight. It should be beautiful."