The following day, everyone was up and about already despite stars still dotting the sky as Senku wanted to ensure that the minerals collected by the expedition group were actually tungsten. To do so, they had to be exposed to ultraviolet light which only becomes visible before sunrise.

Thus, this explained why the village was buzzing with activity even before the first ray of the morning sun made an appearance. While everyone waited for dawn to arrive, some of the villagers were having a go at Senku's birthday present.

"You can see so far away!" Suika shouted in delight as she spotted a pair of deer drinking from the river that was a distance away from the village when suddenly, she noticed the sky lightening. "The sun's gonna rise soon!"

"Don't look at the sun through the telescope," Senku warned the young blonde from outside the observatory.

Next to him, Kohaku glanced down at the basket filled with minerals and muttered, "If the stones you guys got are the right ones..."

Just as she said that said rocks started to glow blue and all of you exclaimed in awe at the sight of it.

"Wow, it's like a mountain of jewels," Ruri commented, sapphire-blue eyes reflecting the tungsten's glow which caused it to sparkle like its namesake.

"It's not like a mountain of jewels. It is a mountain of jewels," the scientist corrected her, his lips stretched into a wide grin as he chuckled in delight. "It's a treasure trove of super rare metals."

"Yay, we did it!" You cheered and exchanged high fives with a beaming Chrome. "Our hard work got paid off!"

Seated on a rock behind the rock was Magma who let out a snort, "Jewels, my ass. They're just slightly heavy rocks. After all that fuss..."

"We're going to win against Tsukasa-chan's army with these rocks," Gen piped up next to the disgruntled blonde.

"With these rocks? I see..." Kokuyo murmured, his brows furrowing in slight contemplation before understanding dawned upon him. Or rather, misunderstanding as he picked up a rock with menacing eyes and his lips twisted into a gleeful smirk, "With these gems! I can see them being heavy enough to really hurt."

You, Gen and Senku wore looks of disbelieved horror, wondering how on earth did the old man come to such absurd conclusion?!

Rui's voice was filled with exasperation as she corrected her father, "Father, I don't think that's what..."

However, she was interrupted by Kohaku who responded without batting an eyelid at the situation, "You can't blame him. Father is of an older generation."

"What?!" Said blonde exclaimed, feeling offended by his daughter's blunt words.

Sweat-dropping, the mentalist tried to change the topic as he pipped up, drawing everyone's attention towards him, "We're up against Tsukasa-chan's army. They're going to be seriously tough."

You nodded your head in agreement, smiling as you added, "Our plan is to make cell phones using these rocks and win the information war."

The others let out murmurs of understanding when Kohaku turned to the scientist with raised brows, asking, "But, Senku, how much longer is it going to take to make our cell phones?"

"She's right," Ginro jumped in and voiced his concern, his panic growing with each word. "Once spring comes, Tsukasa-kun's army is going to be rushing in."

Chuckling, the green-haired teen reassured everyone, "The goal's not that far away. To put it simply...The vacuum tube is the heart of the cell phone. Plastics make up its skeleton. The microphone is the vocal cord. The gold wire is the veins. With these four body parts, we can finish the cell phone."

Hearing that, all of your faces lit up at the good news, filled with motivation once again.

Senku grinned as he continued, "This mega-science project is coming to a close. Everyone, we're sprinting all the way to the goal from here!"

At that, the entire group let out huge cheers that rang throughout the surroundings; determined to finish the last leg of this long race. After all, they had come too far to stop now.

Time skipped

Holding up the glowing gem in his hand, Senku started to explain the agenda for today, "First, we're going to make the filaments, which are essential for the vacuum tubes...using tungsten, the most heat-resistant metal in the universe, sleeping inside this blue light."

"But, Senku, how are we going to get it out of the stone?" You asked, head tilted to the side while furrowing your brows in contemplation. "And why do I have the feeling that it's not going to be an easy feat?"

Your worst fear was confirmed when the green-haired scientist turned to you with a wry grin, letting out a sigh, "You're spot on about that. It's going to be tough as hell to remove the tungsten from inside the mineral itself."

Suddenly, loud banging could be heard coming from somewhere to your right and both of you whipped your head towards that direction where to everyone's shock, Magma and Mantle were whacking the heck out of the minerals like nobody's business.

"What the hell are you two doing?!" Chrome and Kohaku cried out, their eyes bulging in outrage.

The blonde continued what he was doing as he turned to the pair with a calm, yet confused expression and said, "We're getting it out of the rocks, aren't we? All we need to do is destroy it."

"I mean, that works," the scientist sweatdropped at their actions. "We'll be turning it into powder, anyway."

"For a meathead, that's not bad," you laughed, impressed by the blonde's simple but smart thinking.

"See?! I was right!" Magma crowed loudly, sticking his tongue out at both Chrome and Kohaku in a mocking manner.

"No one asked you!" Chrome argued, glaring at the blonde.

Kohaku let out an exasperated sigh, rubbing her head at the oncoming headache whenever she had to deal with the other, "What if you'd been wrong?!"

Kokuyo, on the other hand, blinked once, twice as though he couldn't believe what he was witnessing in front of him. As he continued to watch Magma hammered away at the pile of rocks, he murmured in contemplation, "This is unusual. He's hardly doing it right, but I've never seen him offer to help. Did something happen in the cave?"

He turned to look at both you and Senku with raised brows as he said that, waiting expectantly for an answer. The two of you glanced at each other as you recalled what happened in the cave:

Ocean-blue eyes widened in shock as Magma raised his head as well, his mouth parting in awe as water gushed over the edge of the pit. You grinned when you saw the wonder reflected in those gazes filled with so much doubt not too long ago before looking up as well; (e/c) eyes falling shut in bliss as little droplets of water splashed onto your face.

Senku went on, "You get to see all the insane stuff that humanity worked together for two million years to build. Stuff you never would've seen otherwise. And I'll show you so much of it, it'll make your head spin."

The blonde was too speechless to respond as he kept staring, unable to tear his eyes away. Then, his face softened, and you knew that he was sold by the green-haired teen's words.

---

The two of you braced yourself but were still startled when Magma lifted Senku by his feet as he resurfaced once more, "Senku! I don't care if you're the boss anymore. At least, until we deal with that Tsukasa guy. But if you show me anything lame, I'll kill you!"

With that, he used all of his strength to propel the two of you into the air. You let out a shriek and wound both arms around Senku's neck as you held on for dear life. Luckily, the green-haired teen landed onto his feet safely and as he placed you gently onto the ground, he glanced over to where Magma was still in the hole below and responded, "Yeah, that works for me. There's no way science could be lame."

"Gee, I don't know," Senku answered with a shrug, but no one could mistake how those ruby-red eyes softened as he looked over to the blonde.

You just giggled, grinning secretly to yourself as (e/c) eyes focused on Magma hammering away without a single care in the world; the corners of his mouth quirked up into a small smile.

***

"We're done," Magma announced as he wiped the sweat out of his eyes, his lips curled into a satisfied smirk at a job well-done before turning to Senku with hidden eagerness in his eyes, "What's next?"

Said scientist approached the pile of tungsten now crushed into powder and bent down to scoop a handful of it, grinning as he watched the fine grains fall through the gaps between his fingers, "I'm going to do chemistry stuff to this powdered blue rock to turn it into something resembling toothpaste."

Gen, who was peering curiously at the pile of crushed tungsten, smiled wryly at the teen's words, "Right, you're doing chemistry stuff. The stuff it wouldn't do me any good to ask about."

You turned to the mentalist and gave him the thumbs-up sign, beaming widely as you said, "That's the spirit, Gen! I knew you would get the hang of it!"

Said bi-coloured-haired teen grinned awkwardly, unsure of how to respond and you just laughed before turning your attention back to Senku where you were greeted with a pair of glaring eyes.

"What?" You dragged the word, blinking your eyes innocently at the scientist. "I'm just helping a fellow friend out."

The frown on your boyfriend's face deepened and you rolled your eyes this time around, "Don't give me that look, Senku. I'm just stating the truth since not everyone understands science as you do."

Said teen let out a petulant huff, pouting slightly as he grumbled, "Whatever."

You shook your head in exasperation at his childish behaviour but wasn't annoyed by it; in fact, you found it cute (and secretly happy that Senku was being more open with his feelings around you).

"You're such a big baby," you mumbled before planting a placating kiss on Senku's lips before leaning back and watching in glee as his cheeks blazed crimson like his ruby-red eyes.

The green-haired teen whipped his head around, pupils blown wide in embarrassment as he sputtered, "W-What the hell was that for, you idiot?!"

(E/C) eyes sparkled with mirth, enjoying how flustered your boyfriend was as you responded, "What? Is it a crime to kiss the one that I love?"

Pointing a shaky finger at you, Senku continued, "We're in front of others for goodness' sake!"

You raised a brow at his weak reasoning before facing your friends who were watching this new development between the two of you in varying degrees of amusement, shock, and glee, "Do any of you have any problems with me displaying public affections to my boyfriend?"

"Nope!" They responded with wide grins, some of them trying to hold back their giggles.

Satisfied with their answer, you turned back to the scientist with a smirk and folded arms, "See, no one's mind. So, we're all good."

Senku's gaze narrowed into a glare, his cheeks still a brilliant shade of red before he let out a resigned sigh and brought a hand up to rub between his eyes where he could feel an oncoming headache, "Since when did you get so bold?"

Laughing, you bumped your shoulders against his and grinned cheekily, "Since last night when you return my feelings and I decided to stop hesitating when it comes to my love for you."

If it was any possible, Senku's face burnt deeper at your words as he scowled, "It's not the same thing."

Before you could open your mouth to retort, the two of you were interrupted by a loud cough and both of you turned your heads towards the direction of the sound where Gen was raising a brow, "You were saying about the tungsten?"

"Right," Senku directed a last glare at you as though saying "this wasn't the last of it" before clearing his throat and getting back on track. "As I was saying, we're going to get rid of the rust on the toothpaste stuff using hydrogen, warm it up in a glass container, and it's done. It needs to be at least 1,000 degrees."

"I see, the hotter it is, the stronger the tungsten will be," you mumbled in understanding to which the green-haired teen nodded, a pleased smile on his face.

As the scientist was gathering the fine powder into a small bag, both Chrome and Kaseki were getting the furnace ready as the latter whistled at how easy it seemed, "So all we have to do is cook it."

"Hey, it's actually pretty easy," Chrome agreed.

However, Senku was quick to shut down their thinking as he turned to them with a deadpan face, "What are you, stupid? What would happen to a glass container if you threw it into a fire that's 1,000 degrees?"

The duo blinked once, then twice before realization dropped onto them like a huge boulder. Meanwhile, Senku went on to explain, "We have to heat up just the tungsten toothpaste inside the glass container."

"Then we need a heating mechanism with pinpoint accuracy," the old man was quick to point out, although he didn't look too confident as he said it. "How do we do it?"

With a serious expression, Senku answered, "We don't have time. Let's split up the work. I'll deal with the toothpaste-making chemistry stuff."

"So, who's making the pinpoint heating mechanism?" Chrome asked as he came over, his brows furrowing in confusion. "Are there any other science users?"

Suddenly, the brunette went silent, and you smiled fondly when chocolate-brown eyes lit up with understanding. Seeing how the teen had come to his own conclusion, Senku's lips quirked up into his trademark smirk as he said, "Chrome, you know everything you need to make one from scratch. Throw all the science tricks you've learned at it. Or do you need Senku-sensei's help?"

The corners of his lips curled into a confident grin as Chrome replied, "Don't make me laugh. I'm Chrome! I'm a smart-as-hell science user!"

"That's the spirit!" You cheered, beaming at the brown-haired teen's sureness in himself. "And I'll be here to help as always! So, go for it, Chrome!"

Then, you watched in fond amusement as the duo high-fived each other while exchanging words of encouragement in their unique way.

"Don't come crying for me for help at your lab," Chrome teased while Senku grinned in agreement, "Yeah, I got the lab stuff. I'm leaving you in charge of the heating team."

"You make me jealous," Kaseki, who had been watching the whole thing in silence, spoke up and your eyes trailed over to where he was clinging onto the furnace; his lips twisted into a small, thoughtful frown.

"What do you mean?" You asked with furrowed brows as the other two turned their attention towards him as well.

The craftsman pulled himself upwards, settling down on the top of the furnace before diving into his tales, "You know, I've always loved making things, even as a kid. I made all sorts of things—bridges, shields—so that people wouldn't look at me funny. Thanks to that, I get to pretend I'm still in the game, even at this age."

He let out a wry chuckle before continuing, a sad glint in his kind, wise eyes, "But to be honest, I can't help but wish I had a maker buddy, too."

"But you have three friends, Old Man Kaseki," Chrome pointed out, slightly confused by the other's words. "Maker buddies."

Hearing that, Kaseki glanced up in surprise, not having expected that answer at all. "Three? Where?"

"Right here," the brunette answered as he pointed to himself than to both you and Senku.

Your cheeks flushed a rosy hue at the compliment, smiling sheepishly as you mumbled, "I don't know about being maker buddies since I'm not good at that but friends? For sure, without a doubt."

The old man was stunned by both your words, yet he was still filled with doubts as he hesitantly asked, "Me? Even though I'm almost fifty years older than you?"

"Our age?" Chrome tilted his head to the side, looking like a confused puppy. "That matters somehow?"

You nodded your head in agreement, winking at the craftsman as you gestured to both yourself and Senku, "If you're gonna talk about age, then doesn't that make me and Senku too ancient to be your friends considering we're 3700 years older than you?"

Kaseki's face lit up with hope as his eyes filled with tears of joy to the point that they couldn't be contained and spilt over, flowing down his face in rivulets. Overjoy turned to determination in the next moment as the white-haired man wiped away the tears, the corners of his lips twisting into a confident smirk; his muscles bulging as always whenever he got excited over crafting and building.

"What the hell?!" Both Senku and Chrome exclaimed in shock at the sudden change of the other's mood while you watched in fond amusement as Kaseki got to work straight away.

"He's even more gung-ho than usual," Gen commented with an amused smile as he watched said craftsman crafting away at the furnace with you and Chrome acting as his assistances.

Suddenly, he was startled when he was grabbed by the back of his winter coat by none other than the scientist who started to head for the science lab; dragging the other along with him, "Come help me over here, modern man. You must know at least a little more chemistry than the villagers."

The bi-coloured-haired teen could only go along with Senku's antics, knowing that his refusal would fall on deaf ears, "I'm not sure."

Once they were inside the lab, Senku got to work; grabbing the necessary items that he needed and bringing them over to the large table in the centre of the room as he explained the process to Gen, "I bet you won't get a millimeter of this, so I'll make it simple. Cook the blue gem powder in sodium hydroxide; use seashells, hydrochloric acid, and ammonia to crystalize it; and then bake it and mix it with honey."

Sweatdropping, Gen blinked as he tried to wrap his head around all the information dumped onto him but failed miserably, "Okay! I understood all of that, Senku-chan. Honey! Bake it, and then honey. I got that much."

The scientist fixed a deadpan stare at the mentalist before letting out a resigned sigh, muttering to himself, "Chrome's definitely ten billion times more useful than you. Hell, even (Name) and she's dumb at times."

(On the outside, you let out a sudden sneeze which earned looks of concern from Kaseki and Chrome, but you shrugged it off, saying it was probably from the winter cold. Little did you know.)

"Nah, I don't think anyone could have kept up with that," Gen mumbled with a wry smile. "You're the only one who gets it, Senku-chan."

With that, Senku returned to his chemistry stuff while Gen just hung around and helped with the non-sciencey stuff.

Time skipped

Meanwhile, on the outside, the heating team was getting down to business with the pinpoint accuracy machine.

"Nothing beats this when it comes to pinpoint heating!" Chrome declared in confidence as he held up the large concave glass over his head.

Kohaku clenched her fists in excitement as she exclaimed with a wide smile, "There it is! Chrome's special move!"

Next to her, Magma let out a shudder as he remembered how the brunette lit him on fire during the Great Bout event, "Quit showing it off. You're reminding me of bad times."

You fixed the blonde a sympathetic smile, patting his shoulder in comfort to which he shrugged it off and glared in return, but you weren't offended by it. instead, focusing your attention on