Three months have passed since the start of the construction of Kohaku and Senku's home. Three grueling months of building, resupplying, and overall surviving. Senku dusted his hands off and stood proudly below the structure.

"Here we have it, Lioness. We have completed the first step towards recovering our civilization." He said, looking over to a tired but elated Kohaku.

"Finally I can take a well-deserved break! Am I free to go today Senku?" Kohaku said, beaming over the fact that they now have a well-sheltered home base.

"Yeah go ahead, I have some research to do anyways." Senku waved her off, sauntering over to his laboratory. They somehow managed to build that lab for Senku's experiments and research. Kohaku nodded and skipped over to their makeshift food storage.

Might as well make a celebratory meal for this accomplishment. She thought, taking out different assortments of meat, herbs, and spices that Senku himself prepped up. She briefly prepared a meal for the both of them and put the bowl in the underground storage for marination. She started a fire and sat near the pit, watching the smoke and flames rise. Kohaku gazed her eyes towards the lab and watched as Senku examined a certain pot of wine.

It must be ready for whatever antics he's up to. She pondered, resting her chin on her knees. They started on the wine project over three weeks ago. Senku told her that the liquid would need to "mature" for it to convert into alcohol. She sighed and looked down at her hands. They were quite dry and a bit rough to the touch, but they were somehow overall soft.

Three months have passed. Almost four since she and Senku have been released from that horrible void that was the petrification. Over those three and a half months, things have been going over smoothly, other than the over-excessive amount of work both her and Senku have been doing. Kohaku looked back towards Senku and saw that he was scratching his head as he looked down at a cup with what Kohaku assumed was the wine. She decided to stand up and walk over to him.

"What seems to be the problem, Senku? I see that look of uncertainty from the fire pit." She teased. Senku ceased from his conflict with the cup and smirked.

"Why don't you give it a try Lioness?" He passed the cup to her and stood by. She glanced at the cup and him. She shrugged and gave it a sip.

Well… It certainly tasted like wine. But something was off.

"It still needs to go through the process of distillation, it refines the wine and increases the concentration of the wine, thus making it more strong alcohol-wise." He explained as if he read her mind.

"I see." Kohaku shook the cup slightly and gave it another sip.

The wine was quite easy to make now that she thought about it, all she had to do is crush the grapes and mix the liquid every day to get it where it's at now. How hard could distillation be?

…

Distilling the wine was NOT easy.

They made a huge weird-shaped pot with a tube sticking out, a bowl-like shape on top that was full of water, all made with clay. Senku called this weird looking vessel distillation earthenware. They were both fairly confident it would hold, so they dumped half of a bucket of wine onto the pot. But upon heating, there was a crack in the pot and it broke into pieces, spilling the wine all over the ground. This left an exasperated Senku and a stressed-out Kohaku. They built a firmer one, checking thoroughly for any cracks. They didn't find any and hoped that it wouldn't break like the last. Thankfully, it held its ground, and they went on with their day with work.

Eventually, Fall arrived. Both Senku and Kohaku were preparing for winter. Senku looked down at the pot, contemplating. Kohaku noticed and patted his back, reassuring him. They both have been keeping an eye out on it, watching out for the fire, changing cups, checking for any breakage. There was no trouble with the wine and things have been good since their first attempt.

It was now the middle of winter. Kohaku walked out of a frozen lake, fish on one hand, and spear in another. She trudged towards their home and dropped the fish onto the storage upon arrival. She placed her spear on weaponry she made near a tree. She let out a puff of air and gazed as the fog quickly dissipated into the chilly air. She then went to help Senku with any troubles he had with carrying. It continued like this.

Then Spring came.

Senku wiped his forehead, staring down on a row of purified wine, now stronger in alcohol percentage.

"So, this is the finished product?" Kohaku questioned, picking one of the numbered cups.

"Yep, we've made alcohol." Senku stretched his arms upwards, grabbed a huge lid, and walked out. Kohaku accompanied him with no words. He led her and found themselves back in the very cave where they had been freed from the petrified prison.

They entered the dull cave and Kohaku blinked a couple of times, adjusting to the dimness of the cave. Senku trudged towards the middle of the cave, picking up a huge pot of a strange substance. He shook and quickly Kohaku was by him, taking the pot to herself. She took a closer inspection of the liquid and noticed it was quite yellow.

Before she could ask what it was," it's nitric acid." He murmured. She was taken aback.

"Nitric acid?!" She looked up and took notice of the slumbering bats.

"You know how the nitric acid is made here, right Kohaku?" Senku questions, closing the pot with a lid he had brought along with him. She scoffed mentally, of course, she knew how it was made, but considering it was made in a cave, she'll have to think more. She did work under Senku before all this.

"This acid is made with bat guano, if the cave is moist, the guano layer is also kept moist. So naturally, nitrifying bacteria can process the ammonia in the guano into nitric acid. The droppings are then falling onto the ground. But knowing that this type of acid from this cave won't last long, there has to be some type of alkaline minerals in here." Kohaku explained, inspecting the roof of the cave more closely.

"Correct you are, which is why we need to work on this now." Senku ushered Kohaku out of the cave and the two of them head back towards the lab. Senku quickly got to work and took some other small jars.

"These are other jars that I've been mixing around with the acid and alcohol. So far I haven't tested them out. Each of them has a different amount of acid and alcohol. This one," he raised a cup numbered '6', "will be the one I will be mixing about 30 percent nitric acid and 70 percent alcohol, if it doesn't work, we still have more time to make more attempts, it's all trial and error." He worked on the mixture, being as precise as possible. Once he was clear on the amount, he closed the jar and breathed out. Kohaku finally decided to ask.

"This is probably not the best time to ask, but what exactly are you making?" She wondered, Senku stared at her. She quickly became flustered, "n-neverm-"

"I've worked on this project since before we've gotten petrified. I've conducted experiments on the swallows and their feathers, you could say that with this recipe, or chemical to be more precise, has been in my list of experiments. I've been thinking that somehow our bodies couldn't have been revived based on sheer power alone, so I'm considering that the nitric acid in the cave had an aid with the revival, and will be using it to our advantage." He explained, cracking his neck. Kohaku understood. So staying awake somehow worked in her favor in being free? She wondered if other people fought to stay awake just like she and Senku did but eventually gave up, losing hope of ever being freed. She shook those thoughts away, she didn't need to think of the negatives. She huffed and then wondered.

"Then why do we need alcohol if we already have the nitric acid?" She asked. Senku chuckled.

"If it took us 3700 years just to wake up with the cave's nitric acid, we'll be dead before we use that solution on one single person." He said, grabbing one of the numbered cups and presenting it to her.

"As to answer your alcohol question, we need it to mix it with the nitric acid to make nital. It's a stronger corrosive solvent used for etching among other industrial uses." He said, placing the cup back on the table. Something in Kohaku's head clicked.

"I get it! We're using nital to make a quicker solution of depetrifying the swallows and humans?" She exclaimed, now getting exactly what he meant.

"Yep, and with the numbered cups we have here with different percentages of each element, we can pour some onto the petrified feathers and swallows and see if one of them is the one we exactly need." Senku then proceeded to hand Kohaku cup 1 and 2. He took cups 3 and 4, they separately poured the cups on different petrified feathers. So far, cups 1 and 2 didn't work. Kohaku looked over at Senku and saw his disappointed expression at cups 3 and 4. Guess 3 and 4 were a no-go. Senku stood up from the ground and got cups 5 and 6. Kohaku got 6 while Senku stayed with 5. She walked back to her boulder and breathed out.

Please please please let this be the one, it's been a year now since we've been freed. Give others the chance to find this new world. She thought, looking up at the sky. She hoped. She poured the liquid onto the petrified and waited…

And waited…

She was close to giving up, she stood up to report to Senku before she heard a crack. Then she heard another. She looked back. Her eyes widened.

Before her eyes, was a beautiful feather that has sprouted out of the dull now shattered stone.

She couldn't believe it.

"I- the- Senku-" She turned back in disbelief. Senku was already behind her, looking over her, his own eyes widened. His red eyes went to her blue ones.

"Looks like we've done it, Lioness. We've created revival fluid." His voice sounded like it was wavering, but he stood ground. Kohaku herself felt like crying, but she had to confirm her suspicions, it could've only worked on the feathers. So quickly she grabbed a swallow from the lab and placed it in front of her. She got the cup she was holding not long ago and poured some onto the bird.

Then she waited.

A few moments later she heard those same cracks, confirming her suspicions, it worked on living things too. Before she could speak her thoughts out, the now freed swallow burst from the stone, flew high into the sky, before soaring towards the wilderness, never to be seen again.

She really couldn't believe it.

Senku was smirking proudly, he was just about to head back into his lab and write down his discovery and the exact formula of the fluid before he was knocked down onto the ground. He groaned in pain and looked above him. Kohaku was on top of him, she was crying and sniffling. Before he could say anything to protest, she dropped herself and hugged him. His hands were above her, not knowing what to make of this situation. He looked down, her head and hands were on his chest. He could hear sobs and whimpers.

"You kept your word Senku. You found the solution to free humanity. You and I could see our friends and family again… Thank you so much. Thank you..." She sobbed and looked up to meet his eyes. But when she mentioned family, he kept silent. He briefly wondered about his step-father and his whereabouts, but he quickly snapped back to reality and looked at the woman on him.

What was he meant to say in this situation? Senku was honestly panicking, here above him was his past secretary plus assistant crying and thanking him. He doesn't think science could give him a solution to this. So he thought of the most plausible thing to say.

"This couldn't have been possible if you haven't found those grapes, Kohaku." He said, doing his best of comforting her by placing his hand on her back, he could feel her shaking. He patted her back for a few seconds. She stilled.

She sat up and was now sitting on his lap. Senku started to panic slightly more. Kohaku wiped her tears away and smiled.

"We both know this was all you Senku. If I were to be in this world alone, I would have never progressed this far. I would have probably taken my own life due to the solitude of being truly alone. You kept me going, and made this all possible. You will have my loyalty until death takes me." She studied his wide crimson eyes, which seemed to have softened a bit. She was so grateful to this man. He has helped her out of so many situations, he was the light to her darkness. She needed him. But she knew that deep down, he only saw her as an assistant and assistant alone. She could never have the happiness she oh so craved to have with him. So she decided that perhaps pursuing him at this time is not a good plan. She will bottle these feelings up and stay by his side, as his assistant.

After she had stopped crying, she got off of him and dusted her knees off of dirt. She then helped him back up his feet and let out an embarrassed sigh.

"Sorry for that little outburst I had, I had my emotions get the best of me," Kohaku said. She focused her gaze at Senku, who was looking at the laboratory, back facing her.

"It's alright, you just caught me off guard," Senku responded, coughing slightly.

"Is there anything else that you need me to do?" Kohaku offered, she kinda wanted to get away from him, too embarrassed to be by his side at the moment.

"You can go ahead and do what you want. Tomorrow we can decide who to revive." He said, plodding back towards his lab. She stood and watched before he disappeared from her sight. She went along her way, maybe she should take a quick bath at the river.

Senku went out and peeked as Kohaku went her way to where she was going. He was silent and went back inside his lab. He slowly put a hand to his chest and breathed out. He then raised the same hand and cupped his face. He was blushing feverishly.

"Kohaku…" He whispered. This was a first and he didn't know what to feel. Her words have sparked something in him. The sudden hug and touch surprised him too. He'd heard her thank him plenty of times before, but this one has hit a chord, hard. He didn't know how to deal with these feelings and was confused. He quickly thought out that these feelings shouldn't distract him from his goals. So he pushed those conflicting emotions and continued with his notes.

Tomorrow was going to be a new and exhilarating day.