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Senku has gotten busy ever since they started building the rocket.
Then he gets even busier when he agrees with Chrome’s plan to turn it into a two-way rocket.
The workload multiplies, calculations pile up, and every second is spent adjusting, testing, and rebuilding anything that doesn’t meet his standards. But now, after countless hours of refining the smallest details, only minor adjustments remain.
The two-way rocket is almost finished.
The final piece is the guidance and navigation system—the part responsible for keeping the rocket on course, correcting its trajectory, and making sure it doesn’t end up as a very expensive chunk of metal flying into the wrong direction.
A rocket isn’t just about force.
It needs a brain.
And Senku just built one.
The moment the system finally activates without errors, the entire team gathers around.
Everyone stares as even the ones who don’t fully understand the science behind it can recognize the scale of what they’re looking at.
But Senku doesn’t look at their reactions, instead, his eyes scan the crowd.
And then he notices it.
Gen looks bored. Actually bored.
That never happens, not even once.
Usually, the mentalist is right there, eyes wide with disbelief, throwing out some dramatic comment about how impossible something looks. Gen’s reactions never get old. There’s something oddly satisfying about watching someone who makes a living reading people struggle to process Senku’s inventions.
Sometimes—only sometimes—Senku likes seeing it.
He enjoys being able to surprise Gen.
Senku relishes it even.
So why isn’t he looking now?
Senku narrows his eyes.
Is Gen planning something?
That’s the only logical explanation.
The mentalist doesn’t just lose interest. Everything Gen does has some kind of purpose behind it.
Then Gen looks away from the rocket—away from Senku’s creation.
And his eyes land on Xeno, who is working on the other side of the launch site.
Xeno is finishing the final adjustments on the rocket’s propulsion calculations and engine efficiency systems—the part that determines whether all of Senku’s carefully designed technology actually gets off the ground.
A different piece of the same impossible machine. And, annoyingly, just as impressive.
Gen’s expression changes.
His usual bored face disappears as his eyes widen. “Oh, that’s amazing, Xeno-chan!”
Senku freezes.
…Huh?
What?
He watches as Xeno immediately grins, clearly pleased by the reaction, before starting to explain the engineering behind his work.
And Gen listens to him carefully.
But… that’s supposed to be Senku.
Senku is supposed to be the one explaining.
He’s supposed to be the one making Gen stare in shock, making him throw out some ridiculous compliment, making him look like he just witnessed something impossible.
That reaction belongs to only Senku. Not Xeno.
Senku narrows his eyes again.
Gen is planning something.
He has to be.
There’s no other explanation, because if he isn’t…
If Gen genuinely isn’t amazed by Senku for once…
Then this will be the first and last time the mentalist ever gets away with not being in awe of him.
***
Except, it’s not the last time, but it is definitely the first.
“Oh, Sai-chan!”
Gen’s voice cuts through the noise of the launch site, and Senku immediately looks over.
The mentalist is already hovering near Sai, who is sitting in front of one of the computers, fingers moving quickly across the keyboard as lines of code fill the monitor.
“What are you doing?” Gen asks, leaning closer.
Sai looks up, slightly surprised by the sudden attention. “I’m adjusting the navigation program. The rocket’s trajectory calculation needs to account for the moon’s position, gravitational influence, and the time difference between launch and arrival. Even a small error in the numbers can cause a huge deviation once we’re dealing with a distance like this.”
He points at the screen, explaining the calculations behind it. Gen looks at him in wonder.
“It’s basically predicting where the moon will be instead of where it is now. Since both the Earth and the moon are moving, we have to calculate the future position using orbital mechanics.”
Gen stares at the monitor. “You’re amazing, Sai-chan.”
Sai pauses, then his face immediately turns a little red, a small smile appearing as he looks back at the screen.
Senku watches the entire exchange.
There’s just a slight disruption within him… in the usual order of things, like a perfectly balanced equation suddenly gaining an unnecessary variable.
Because Gen is supposed to look at Senku’s inventions like that.
The other day, that look belonged to Xeno, but now Sai?
Gen's is supposed to have that expression when Senku explains something impossible, when he reveals some new piece of science that shouldn’t exist.
Senku clicks his tongue quietly. Annoying.
Fine. If that’s how it works, then there’s still plenty of science left to show.
While Sai continues working, Senku moves toward an empty terminal nearby. Since they’re already surrounded by computers and equipment, he starts modifying one of the programs they use for the mission.
A better simulation, and more efficient calculation system.
Something that can process the rocket’s flight data faster, predict possible errors, and adjust the route before the problem even happens.
When Senku finishes and shows everyone the updated system, the reaction is there.
The group gathers around the screen.
“No way, that’s baaaad!” Chrome says, staring at the results.
“Of course it is,” Kohaku replies, although even she looks impressed.
The others begin talking among themselves, amazed by how much faster and more accurate the calculations become.
Senku can’t help but feel that familiar rush of pride, not because it’s some impossible miracle, it’s just science.
A process anyone can achieve if they put in the effort.
Still, watching everyone’s faces makes something in his chest settle.
Then he looks for Gen. And his expression drops.
Because Gen is smiling.
But it’s wrong.
It’s the kind of smile he gives people when he’s performing, when he’s trying to convince someone of something. His mouth curves upward, but his eyes are empty, not carrying the usual spark of genuine interest.
He notices every small change in Gen.
The angle of his head, the way his eyes move, the difference between a real reaction and a fake one because that's literally what Gen does for a living.
Then Gen’s eyes meet his. For a second, Senku expects another fake smile.
But instead, Gen smiles again.
This time, it’s real.
And immediately, something inside Senku eases.
It’s ridiculous.
A simple facial expression shouldn’t have this kind of effect. It’s just a combination of muscle movements, emotional response, and social signaling.
A completely explainable biological reaction.
So why does it feel like a weight disappears from his shoulders the moment Gen smiles at him?
Gen looks away, and the moment disappears.
Maybe… maybe Gen isn’t losing interest.
Maybe he’s challenging Senku.
That’s the only conclusion that makes sense.
Because seriously, why would Gen suddenly stop reacting to Senku’s inventions? The mentalist spends his entire life studying people. He knows exactly how rare these moments are, how impossible the things they’re building should be.
Gen doesn’t get bored.
Not with science.
Not with Senku.
So if he’s deliberately holding back those reactions, then there has to be a reason. And Senku is going to figure it out.
Because there is no way Gen is getting away with changing the variables of their usual pattern without Senku finding out why.
***
Senku tells himself that he is only slightly frustrated.
A tiny bit, barely even worth mentioning.
It’s not like Gen’s reactions are important or anything. It’s not like Senku expects the mentalist to look at every single invention with wide eyes and endless commentary.
That would be ridiculous.
But still… What exactly is going on?
Because Gen is still amazed.
Just not at him.
Whenever Kaseki finishes building another part of the mission control center, Gen immediately appears next to him, staring at the creation like he’s witnessing some impossible work of art.
The communication equipment, control panels, and the complex network of machines that allows them to monitor the rocket and stay connected during the mission.
Gen reacts to every single detail. “Seriously, Kaseki-chan, this is incredible.”
And every single time, Kaseki’s expression brightens.
Senku watches from a distance.
For a moment, an annoying thought appears.
Maybe it’s because Kaseki had both Senku and Xeno helping him, and… Gen is impressed because the inventions are connected to something Senku created.
But Senku immediately dismisses the idea.
No.
That’s wrong.
Kaseki’s work is amazing on its own.
The old man’s craftsmanship is something even science can’t replace. Having assistance doesn’t erase the skill, effort, and experience needed to turn an idea into something real.
Still…
Why is Gen not reacting like that to him? And when Gen needs an explanation, he always goes to Senku. Always!
Later, Chrome walks over with another idea.
Another one of his ridiculous flashes of inspiration.
It’s something that already exists in the modern era, but the fact that Chrome is able to think of it after being born three thousand years later is still impressive.
A better monitoring system. Something simple by modern standards, but an incredible leap considering where they started.
“No way, Chrome-chan. That’s actually enius-gay.” Gen comments in awe.
Senku freezes.
Again.
He watches as Chrome lights up at the compliment, his confidence growing as Gen continues talking about how amazing the idea is.
And Senku knows Gen is right.
Chrome’s idea really is brilliant.
The guy was literally born after civilization collapsed and still managed to reach the same conclusions humanity once spent centuries developing.
That’s not something to ignore.
Senku understands that. He understands it perfectly, ten billionth percent.
So why is there this strange feeling in his chest?
A slight pressure that feels like a minor disturbance, like a system detecting an error that shouldn’t exist.
It’s not jealousy. That would be completely illogical.
Chrome deserves the praise, Kaseki deserves the praise, and everyone deserves the praise they’re getting.
So why does Senku keep noticing that Gen’s amazement is no longer directed at him?
Senku looks away.
Maybe he just needs to build something better. Something that even Gen can’t ignore.
But then again, the rocket is nearly complete, the space suit is almost finished, the mission control center is already functioning, and there isn’t exactly some impossible invention left waiting to be created.
The only thing Senku needs to do is continue making things that improve everyone’s lives.
Like… A smartphone, which he was already planning to create for Taiju.
Yeah. That would be useful.
And if Gen happens to be impressed by it too… Well.
That’s just another successful scientific advancement.
Nothing more obviously.
***
“You’ve been ired-tay lately, Senku-chan.”
Senku looks away from the stars to see Gen approaching in his direction.
They’re standing inside the new observatory hut, a rebuilt version of the one they had years ago. The original structure had been left behind when everyone was petrified for seven years.
Now, after continuing to rebuild civilization from nothing, they recreate the hut almost exactly as it was before, preserving the same feeling of the place while adding a few improvements that make it sturdier and more practical.
“You should go to sleep, mentalist,” Senku mumbles, turning his attention back toward the sky.
“I should say the same thing to you.” Gen stops next to him, looking upward at the stars scattered across the night.
Senku scoffs. “I’ll be fine.”
“Sure you are.”
“I am.”
“Interesting,” Gen hums. “Because your current ondition-cay suggests otherwise.”
Senku glances at him. “My current condition?”
“Yes. Lack of proper rest, excessive workload, and an obvious increase in your tendency to stare dramatically at the sky like some tragic main character.”
“I’m literally observing the stars.”
“Of course you are, Senku-chan. And I’m sure the stars are very impressed with how dedicated you are.”
Senku rolls his eyes. “Still annoying after all these years.”
“Thank you. I will work hard at it.”
The corner of Senku’s mouth almost moves, but he quickly looks away.
Gen clears his throat, his voice becoming a little quieter. “You’ve been… frazzled these past few weeks.”
You think? Senku doesn’t say it.
Instead, he studies Gen’s expression.
The mentalist’s eyes are focused on him now, not the stars, not the machines, not anything else.
Him.
“How about you?” Senku asks instead. “From where I’m standing, you’re worried about something.”
Gen smiles at him wryly. “I think you and I know what I’m orried-way about.”
For a mentalist like Gen, it meant a lot for him to admit it that much, considering he hides a lot of things from many people. Then again, it’s not like Senku can't easily deduce it. They’ve known each other for so long anyway.
And yes, besides the fact Gen was lacking reactions to Senku’s inventions, he also noticed how worried Gen is with the moon mission.
Everyone is, actually.
Not that Senku can blame them when there’s a chance Senku, Kohaku, and Stanley are going to risk their life there—especially the fact they don’t know what’s coming to them.
“Look at the dark circles under your eyes.” Gen shakes his head disapprovingly.
Just like that, the topic bounces from one place to another. Like a mentalist he is.
“Am I that obvious?” Senku asks.
“In the eye of the mentalist?” Gen tilts his head slightly. “Yes, it’s obvious.”
Then does that mean Gen knows?
Does Gen know what he’s doing to Senku?
That Senku has been spending the past few weeks trying to figure out whether the mentalist is planning something, whether he’s deliberately holding back his reactions, or whether he simply doesn’t care about Senku’s inventions anymore?
Huh.
Wait… Why would Senku even care about that in the first place?
The thought makes no sense.
He has the moon mission to worry about. There are countless problems that still need solutions before they can leave Earth and reach the moon.
So why is he wasting brain power analyzing Gen?
Senku stares at him.
And Gen stares back.
For once, neither of them says anything.
Now that his mind is already running, Senku finds himself looking back at all the years Gen has spent beside him.
The mentalist has always been there.
Not just as someone useful, not just as another member of the Kingdom of Science, but as someone Senku has slowly come to rely on without even realizing it.
Gen is always there when Senku works too long without stopping, appearing with tea before Senku even notices he needs it. He’s always there to point out things Senku ignores, offering advice that somehow manages to be annoyingly accurate despite coming from someone who spends half his time being dramatic.
He understands people and situations. And somehow, he understands Senku too.
When Senku thinks about it, Gen’s role in his life is not that different from how Taiju relies on Yuzuriha.
A constant presence.
Someone who makes everything feel a little less impossible.
Except—
Senku doesn’t finish the thought as he reaches out and takes Gen’s hand.
The action surprises even himself.
Gen’s palm is warm against his own, the heat transferring through their skin in a way that is completely explainable. Human bodies naturally produce warmth through metabolism, blood circulation, and the regulation of internal temperature.
There is nothing unusual about it.
Nothing strange. And yet, Senku doesn’t let go.
That part is strange. He has never been someone who seeks physical contact. Touch is unnecessary. It doesn’t increase efficiency, solve problems, or create better results.
But holding Gen’s hand doesn’t feel like a distraction.
It feels… Comfortable.
A strange sensation in his stomach.
A sudden drop, almost like the brief shift of weight when an object falls, except there is no physical movement causing it. Just a reaction from his own body, a combination of adrenaline, nervous system activity, and some unknown emotional response his brain refuses to categorize properly.
Interesting.
Not bad.
Actually… It's good.
Senku is not entirely sure what that means.
He looks up and sees Gen staring at him, his eyes widened in surprise.
For once, the mentalist looks completely caught off guard.
Before Gen can say anything, Senku lifts his other hand and reaches toward his face, placing his palm against his cheek.
The warmth is different there.
The skin is softer and the temperature slightly higher compared to his hand. A small change in Gen’s expression, a shift in his breathing, a brief pause in his usual effortless composure.
Senku observes it all, finding the answer to something that doesn’t make sense yet.
He then leans forward without noticing the way Gen’s breath catches.
His hands slowly leave Gen’s face, moving down instead, almost as if he is still trying to understand the strange reaction his own actions are causing. His arms settle around Gen’s back, pulling him closer, and before he can properly process it, he’s already hugging him.
And somehow… It feels nice.
There is no logical reason why this should feel different from any other physical contact. A hug is just pressure, warmth, and the exchange of body heat. It is a simple human action with no complicated mechanism behind it.
Yet Senku doesn’t immediately pull away.
His face rests against Gen’s neck, and he notices another detail he has somehow never paid attention to before.
Gen smells nice.
Not the artificial kind of scent from some perfume that tries too hard to be noticed, but something lighter. A faint floral scent and mixed with the familiar traces of tea, machinery, and the environment around them.
Something that feels strangely like Gen.
“...Senku-chan?”
Gen’s voice breaks through his thoughts.
Senku blinks.
Only then does he realize what he’s doing.
He pulls away from Gen, slowly stepping back.
The mentalist is staring at him as his mouth is slightly open, his usual confidence completely disrupted.
Senku only blinks in return before looking at him carefully. “I see.”
Gen stares. “What do you mean, ‘I see’?”
Senku ignores the question, his mind already organizing the information he gathered.
So that’s it. That’s why he’s been so focused on Gen.
That’s why he kept noticing every change in his reactions, every time Gen looked impressed by someone else’s work instead of his.
It was about Gen. Specifically, Gen looking at him.
Senku has spent weeks trying to solve the wrong problem.
“Um.” Gen’s voice pulls him back. “What was that, Senku-chan?”
“Conducting an experiment.” Senku answers immediately as his eyes shift toward the floor as he tries to sort through the results. “Maybe a hypothesis.”
Gen simply stares at him, then he shakes his head slightly. “Of course it is.”
Senku looks back at him.
“Even though I have absolutely no idea what you just did, knowing you, there’s robably-pay some kind of logic behind it.” Gen tilts his head. “So?”
“So?”
“How was it?”
Senku blinks. “How was what?”
“The hypothesis, Senku-chan.”
Gen sighs, almost fondly.
Senku studies him for a moment.
The question should be easy.
The results should be easy.
He should already have a conclusion, but somehow, the answer is more complicated than expected.
“It was…” Senku stops and looks away. “Acceptable.”
Gen’s eyebrows raise. “Acceptable?”
“It wasn’t unpleasant.”
For some reason, saying that out loud makes Gen look even more surprised.
Senku clears his throat. “I think it’s time to go back to my lab.”
“What?”
“Yeah. I got an idea.”
Before Gen can ask anything else, Senku turns around and starts walking away.
“Wait, Senku-chan!”
But Senku is already moving faster. Running, actually.
He’s glad he turns away before Gen can see the warmth spreading across his face.
Even after figuring out one variable, there is still another unanswered question.
Why is Gen no longer reacting to his inventions the way he used to?
That remains the real problem.
And that is what Senku needs to focus on.
Definitely.
***
Senku keeps making things for everyone.
A washing machine, a video camera, a microwave so cooking becomes faster and more efficient. And, eventually, a smartphone.
Every time, the reactions are exactly what he expects. Everyone is amazed and excited.
They look at his inventions like they are witnessing something impossible.
And yet… And yet Gen doesn’t react.
Not even once.
But when Kaseki mentions another invention idea, Gen immediately lights up.
When Chrome comes up with something clever, Gen praises him.
When anyone else creates something impressive, Gen is there with his usual dramatic reactions.
So why not Senku?
The thought keeps repeating in his mind like an error message he cannot clear.
It’s irritating.
It’s also a distraction that is a completely unnecessary variable that keeps interfering with his calculations.
The worst part is that Senku knows it isn’t about the inventions themselves. He knows Gen is still interested in science. He knows Gen still understands the value of what they’re creating.
So why does it bother him that Gen’s attention is no longer directed toward him?
It’s not jealousy.
Obviously not.
That would be childish.
Senku doesn’t get jealous over something as meaningless as another person receiving attention.
That’s not logical.
But still… The fact that Gen doesn’t even glance in his direction after Senku creates something new is strangely annoying.
Actually, it’s extremely annoying.
So Senku decides to handle it directly.
Subtlety has never been his strength anyway.
He tries approaching Gen whenever there’s a chance. He tries starting conversations, asking about his thoughts, even creating small opportunities where they might end up alone.
But somehow, every attempt fails.
If Senku is working outside the lab, Gen suddenly has somewhere else to be. If Senku finishes an invention and expects Gen to appear like he usually does, Gen is already busy talking with someone else. If Senku walks toward him, Gen somehow ends up surrounded by other people before Senku can even say anything.
And it keeps happening. For days.
It’s long enough that Senku starts noticing a pattern.
Gen is avoiding him, isn’t he? Why?
“Do you want something, mentalist?” Senku asks it bluntly.
There is no point waiting anymore.
The question catches Gen completely off guard, his eyes widening in surprise.
Around them, the entire dining area goes strangely quiet.
Their friends are not even trying to hide that they’re watching now, all of them pretending to focus on their food while obviously paying attention to the conversation happening in front of them.
Normally, Senku would prefer a private conversation but Gen has been avoiding every opportunity for one.
So Senku creates his own.
“What do you mean, Senku-chan?” Gen slowly places his chopsticks down.
“I asked everyone here what they wanted me to build,” Senku says, staring directly at him. “So you should too.”
“Oh, that?” Gen tilts his head, acting far too casually. “Don’t orry-way. I don’t need anything.”
Senku stares at him.
For a moment, he genuinely has no response.
Not once in ten billion years does he expect that answer.
He expects Gen to take the opportunity immediately.
A request or maybe a challenge.
Something impossible that would give Senku another chance to create something amazing—something that would make Gen look at him the way he used to.
“...Not even cola?”
Gen shrugs. “Francois can make that for me.”
Senku continues staring.
The entire plan depends on Gen wanting something.
For one second, Senku feels like the entire world shifts slightly off its axis as a strange, uncomfortable sensation settles within him.
He takes a breath.
Fine.
This is fine.
Gen watches him carefully, his eyebrows drawing together. “Senku-chan?”
Almost everyone is looking at him now with concern.
This is not fine.
Senku has had enough.
Without thinking any further, he reaches out, grabs Gen’s wrist, and pulls him away from the dining area.
“Wha—”
Gen barely gets the word out before Senku keeps moving.
He ignores the confused looks behind them and leads him away from the noise, toward a quieter section near the edge of the village where they can talk without everyone listening in.
A place where Gen can’t dodge the conversation.
Once Senku knows for sure that they are alone, he finally lets go of Gen’s wrist and turns around to face him.
“Now, speak.” Senku demands.
Gen blinks at him.
“So idiculous-ray,” he says, although the confusion in his voice is obvious. “You drag me all the way here and demand an explanation for something, but I have absolutely no idea what you’re expecting me to explain.”
Senku scoffs. “Seriously? You don’t know?”
Gen slowly shakes his head.
For a second, Senku just stares at him.
So Gen really doesn’t know.
Even if Gen doesn’t understand what’s happening, Senku still needs an answer. Otherwise, his brain is going to continue running simulations about this until he loses valuable sleep over a problem that shouldn’t even exist.
“Why aren’t you reacting to my inventions lately?”
The question comes out more directly than anything else.
“Oh…” Gen takes a small step back, a faint blush appearing on his face as he looks genuinely caught off guard. “Why are you asking me that?”
“Because something is obviously going on with you,” Senku says. “I’ve been trying to figure out what’s happening for the past few weeks, so I’m asking you directly.”
Gen stares at him, then slowly, his usual playful expression returns.
“Oh my.” A teasing smile forms on his lips, his smile widening. “Is someone worried? My, my, my, Senku-chan. Is that why you’ve been so frazzled lately? Because I haven’t been giving you the reactions you want?”
Senku doesn’t deny it.
It makes Gen pause.
“Wait.” Then his teasing expression shifts slightly, replaced by genuine curiosity as Gen tilts his head. “Why are you actually bothered by my lack of reaction to your inventions?”
He studies Senku carefully.
The mentalist is working now.
Analyzing.
He’s breaking down every detail, every behavior, every little sign Senku has shown without realizing it.
Senku watches him do it. And strangely enough, he finds it interesting.
Gen is always confident when he reads other people, but watching him try to understand Senku is different.
Gen’s eyes narrow slightly as he connects the pieces.
“Come to think of it, you were watching my expression every time you showed everyone your inventions.” Because this time, the subject is himself. “You weren’t just ooking-lay at everyone’s reactions. You were looking for mine.”
Senku doesn’t interrupt.
“Then there was the observatory…” Gen stops as his eyes widen slightly. “And that’s when you—”
“I figured out I like you at that time.” Senku cuts in smoothly, picking his ear. “Yes, it’s romantic.”
Gen freezes completely.
For once, the mentalist has no immediate response.
Senku simply looks at him, waiting.
“Anyway,” he continues, completely unfazed, “back to the topic. Why haven’t you been reacting to my inventions, mentalist?”
Gen just stares.
It might be the third time Senku has seen him genuinely speechless.
Which is, honestly, impressive.
The mentalist who can manipulate entire groups of people and the guy who always has something to say.
—is completely silent.
Senku casually picks at his ear with his pinky while waiting for the answer.
Eventually, Gen sighs. “I should have known that if you ever confessed to someone, it would be the least romantic confession ossible-pay.”
Senku raises an eyebrow. “I wasn’t trying to be romantic.”
“Yes, I noticed.” Gen rolls his eyes. “Try harder, Senku-chan. I’m not exactly easy, you know?”
“Sure.” Senku shrugs.
“...Seriously?” Gen shakes his head, a small amused smile appearing on his face. “Anyway, about my lack of reaction…”
He pauses.
Senku finds himself waiting in anticipation.
Time to fix the problem.
“It’s because Ukyo-chan teased me.” Gen’s smile turns a little embarrassed. “He said I was being too obvious with my pining for you. Apparently that includes the way I react to your inventions every single time.” He looks away briefly. “Though I onestly-hay didn’t think you would notice that.”
This time, Senku’s brain actually stops.
For a few seconds, the entire chain of thoughts he has been building over the past few weeks simply collapses.
Gen wasn’t losing interest.
He wasn’t bored and wasn't trying to challenge him, just trying to hide how obvious he was being.
“So yes, Senku-chan.” Gen looks back at him, smiling. “I like you back.”
Senku knows he likes Gen.
He already figured that out.
The realization had come with enough evidence and observations, things that even he couldn’t deny it anymore.
But having those feelings returned is an entirely different variable.
It is something Senku would have prepared for if he had the time. He would have calculated the possible outcomes, predicted every reaction, and decided the most efficient approach.
And yes, he would have confessed eventually.
Because Senku knows himself.
He knows that if something stays unresolved long enough, he will eventually say it. The only scenario where he wouldn’t is if Gen already had someone else in mind, it would have changed the entire equation.
Fortunately, that possibility no longer matters.
Senku reaches out and pinches Gen’s cheek. “That’s stupid.”
“Aw!” Gen immediately grabs his wrist. “What’s with that?”
“You’re cute.”
Gen freezes.
Again, the mentalist has absolutely nothing prepared.
His face turns even redder, and Senku finds himself staring.
Interesting.
Very interesting.
It feels like discovering something completely unexpected, something that was always there but remained unnoticed until the exact right conditions revealed it.
Like finding a new species hidden in an unexplored environment. Like observing a distant planet that suddenly appears through a telescope.
Gen’s expression is something Senku never considered important before.
The way his eyes brighten when he’s genuinely surprised, his confidence falters for a moment when he doesn’t have a clever response ready, his head tilts when he’s teasing someone, but also when he’s quietly studying them, and the way his words can be used like a weapon, yet somehow become softer when he’s sincere.
Senku has spent years studying the world.
The stars, earth, and science itself.
And somehow, one of the most fascinating discoveries is standing right in front of him.
Ishigami Senku is fascinated by Asagiri Gen.
…Maybe the lack of reaction was never the actual problem. Maybe Senku had just grown accustomed to collecting every small change in Gen’s expression, studying every smile and every reaction like a discovery he never wanted to finish observing.
“Are you sure you don’t want anything from me before I leave?” Senku asks.
Gen shakes his head. “It’s fine, really.”
Senku tilts his head. “Then can I give you something?”
“Sure?” Gen blinks and smiles slightly albeit unsure. “I don’t ind-may either way.”
Decision made.
Senku steps closer.
Slowly, he removes the red cape from his shoulders, the one with the familiar e=mc² symbol written across it.
Gen’s mouth falls open but Senku ignores the reaction as he simply places the cape over Gen’s shoulders.
Before Gen can properly process what just happened, Senku leans forward and kisses him.
For someone who can calculate rocket trajectories and solve problems involving impossible odds, Senku discovers that this is a completely different kind of experiment.
There is no formula as there is no exact measurement.
He hesitates for the smallest moment, unfamiliar with the rhythm of it, but Gen quickly understands and guides him, making it easier.
And somehow, Senku learns.
The kiss stays soft and closed, lips pressing together in a gentle, unhurried touch. Senku feels the warmth of Gen’s mouth against his own, the slight give of skin meeting skin, nothing more than that simple contact. Gen tilts his head just enough to fit better, and Senku mirrors the motion without thinking, letting the pressure linger a second longer before they ease apart.
At the same time, Senku’s hands stay loose at his sides, but his fingers twitch once, wanting to touch, to anchor himself in this new, uncharted feeling. A moment later, Senku reaches out to Gen’s waist and cheekbones, steadying himself and wanting more.
The softness surprises him again, how Gen’s mouth yields just enough under the pressure without parting, how the faint scent of tea clings to his skin and mixes with the heat building between their faces.
He notices the tiny shift when Gen’s lower lip moves slightly against his own, the way it sends a quiet spark down his spine that has nothing to do with science and everything to do with the person in front of him.
The kiss stretches a little longer than the first, still closed, still gentle, yet it leaves Senku aware of every small detail—the slight dampness at the corner of Gen’s mouth, the way their noses brush, the quiet sound of fabric shifting as Gen leans in closer.
When they finally ease apart, Senku keeps his eyes half-lidded, studying the faint flush across Gen’s cheeks and the way his own heartbeat refuses to settle back into its usual rhythm.
Senku stays close enough to see Gen’s reaction.
Then Senku grins.
“Bring that back to me, Gen.” Senku’s voice turns into a whisper. “Once we get back from the moon, hand that to me.”
Gen looks down at the cape resting over his shoulders, fingers lightly touching the fabric. For once, he doesn’t immediately have a teasing response ready.
He swallows. “Why are you giving this to me in the first place?”
“To remind you that I’ll get back home.”
Senku’s smile softens slightly. Gen blinks at him in surprise.
Everyone is worried about the moon mission.
Even if they trust his calculations, even if they know the amount of preparation and science behind it, there is still uncertainty. Space is unpredictable. The universe has never cared about how confident humans are.
And Gen…
“That's—” Gen stops, biting his bottom lip slightly. “Thank you, Senku-chan.”
Senku watches him carefully.
The reaction is different from the ones he used to look for.
Not a shock nor amazement, maybe wistful and a bit of gratefulness, or well almost shy. Senku wants to observe Gen’s face a lot longer.
“And,” Senku adds, “to remind everyone you’re mine.”
Gen blinks. “Wha—”
“I now acquire you, Asagiri Gen.” Senku grins. “Get excited.”
Maybe the wording is a little strange. To anyone else, it sounds like the same way he talks about every person and resource he’s gathered over the years.
The Kingdom of Science.
The people who joined him.
The impossible things humanity manages to reclaim.
But Senku knows Gen. And Gen knows Senku.
There is no way the mentalist doesn’t understand what he means.
Predictably, Gen laughs.
His face turns red as he shakes his head. “Alright, Senku-chan.”
Then Gen pulls him back into another kiss.
And this time, Senku doesn’t need to analyze it.