Episode 4: “The Steamy Hot Spring Romance Case Files ④ ~Voices Echoing in the Rock Cave~”

We left the inn and headed for the public baths, the pleasant clatter of our geta echoing with each step. The girls seemed delighted by the rhythm, their voices bubbling with excitement as we walked through the evening air.

Our first destination was a place called ‘Ni-no-yu.’ According to local legend, a famous doctor from the Edo period once proclaimed that ‘Fujimi-no-yu had no equal in all the land,’ which is how this particular bath earned the character for “ni” (two) in its name. The specialty here was something I’d never experienced before—a ‘rock cave bath.’

They’d carved one large opening into a natural boulder, then erected a divider down the center to separate the men’s and women’s sides. Unlike a typical outdoor bath, this was a bath inside a massive stone hollow, and as a hot spring enthusiast, my heart raced with anticipation at encountering something so unique.

While trying to contain my excitement and listening to the girls’ animated chatter, the wooden sign reading ‘Ni-no-yu’ came into view. Come to think of it, there was definitely one silver lining to this combined family trip and training camp being at a hot spring resort.

“Well then, Majima-senpai,” Hinata said with a slight bow, “I guess this is where we part ways, isn’t it?”

“Yeah, looks like we’re splitting up here.”

That’s right—hot springs are separated by gender. Which meant I no longer had to worry about navigating the constant presence of the girls. My dad and his friend were suppose      to join us later, having told us to go ahead first. Finally, I was able to      enjoy some time to myself.

“I’ll be so lonely without you~”

“Ahh, what a relief, seriously,”

Setting Nishiyama’s theatrics aside, I glanced at Akira’s anxious expression. For her, this was the first time visiting a hot spring with friends, and I found myself slightly worried. But it wasn’t like I could accompany her into the women’s bath.

“Well then, Akira, have fun, okay?”

“Yeah. See you later, aniki,” she replied with a small smile.

I turned to Hinata. “Hinata-chan, have fun too, okay?”

“Yes! Come on, Akira, let’s go!” Hinata took Akira’s hand eagerly.

“Yeah!” Akira’s nervousness seemed to melt away as they walked hand-in-hand through the noren curtain together. Watching them disappear inside, I felt my concerns ease—there was clearly nothing to worry about.

And so I naturally separated from the girls, which brought me a measure of peace. I could finally enjoy a brief moment of freedom in the hot spring without a care in the world—or so I thought.

＊　＊　＊

After thoroughly washing myself, I settled into the large indoor bath first. The intoxicating blend of hinoki cypress and sulfur that had been teasing my senses all evening finally enveloped me completely, and the sensation was beyond description.

“Kuh-haaaah~~~~~~~…”

The involuntary sigh that escaped my lips seemed to carry away all the journey’s fatigue, dissolving it instantly into the mineral-rich water. These were the moments that made me grateful to be born Japanese.

After savoring the indoor bath, I opened the door that led      outside. Before me stretched the remarkable rock cave, with a divider to my right separating the women’s section. You could call this a semi-outdoor bath, I supposed. I hadn’t seen it in any of the online photos, but as I approached the cave opening, I could glimpse the mountain slope beyond, autumn leaves gazing down like silent observers.

Just as I stepped into the hot spring, the other visitors departed as if we’d arranged the perfect exchange. I continued deeper into the cave and settled in comfortably. Perhaps it was the novelty of the surroundings—being embraced by a hot spring within this natural stone chamber—but I felt a pure, simple joy bubbling up inside me.

When I sank in up to my shoulders, the temperature felt slightly cooler than indoors, but the water maintained that perfect warmth you could luxuriate in forever. It truly felt magnificent.

Eventually, I found myself completely alone, with this wonderful rock cave bath all to myself.

“This is the bessssst~~~~~~~…”

And as I was savoring that precious moment of solitude—

“Wow, this is amazing, isn’t it~~~!”

Suddenly, a voice that unmistakably belonged to Hinata echoed through the rock cave.

That’s when it hit me with startling clarity. Unlike a regular outdoor bath, being enclosed within a cave meant that sounds would naturally echo and amplify. Even though we were separated by a divider, voices from the men’s side and voices from the women’s side were probably almost perfectly audible to each other.

In other words, this is what would inevitably happen—

“Look, Akira, over here, over here.”

“W-wait, hold on, Hinata-cha… hyah! Ow ow ow…”

“Are you okay, Akira?”

“Y-yeah… I just hit my butt… Ah! My towel!”

“Akira, here.”

“Th-thanks… I’m so embarrassed that Hinata-chan saw everything…”

“We’re both girls, so there’s nothing to be embarrassed about.”

“But still, my chest is so small…”

“You don’t need to worry about that at all. Akira, your skin is absolutely beautiful.”

“You’re the one with gorgeous skin, Hinata-chan. Can I… can I touch it a little?”

“Eh? Wait there… Akira, that tickles!”

“Wow, so soft! It feels amazing! And so smooth!”

“Hey, I said stop! Jeez, Akira!”

“Hyah! Hinata-cha, I said that tickles!”

“Here, here, payback time ♪”

A remarkably vivid exchange between the two girls came through with crystal clarity. Akira and Hinata, acknowledging their differences, being modest about themselves, praising each other, and deepening their friendship through innocent physical contact.

I found myself imagining that heartwarming scene, visualizing it, and picturing it in detail…

Wait, no! What am I trying to imagine here?

I hurriedly shook off those inappropriate fantasies, forcing myself to think of something else entirely.

I immediately tried to convince myself that these voices didn’t belong to the Akira and Hinata I knew. If I didn’t maintain that fiction, I’d become a despicable lowlife—worse than any brother should ever be—getting entertainment from imagining my own sister and my friend’s sister in such a situation.

I wouldn’t be able to face either of them again, and I’d have no idea what expression to show Kousei from now on.

So they weren’t them. They were probably just other people with the same names, whose voices happened to sound vaguely similar by coincidence.

Right. That girl named “Akira” had used “boku” to refer to herself, but girls who use “boku” aren’t that rare, probably. Besides, the Hinata I know isn’t the type to get playful revenge when she’s being teased… probably.

For now, I’d just ignore everything and soak peacefully—

“Whoa! This is incredible! Amane, I’m genuinely moved just looking at this!”

“Hehe, I hear first-timers usually react exactly like you do, Kazusa-chan.”

Ah, that pretty much confirms it’s definitely them…

Now that even Nishiyama and Ito’s first names had been clearly mentioned, I had no choice but to accept reality.

“By the way, Kazusa-chan, could you please stop tugging on my towel?”

“It’s fine, it’s not like it’ll wear out or anything ♪”

“Honestly. Don’t act like some perverted old man in a place like this, okay?”

“But Amane is just so pretty~”

“Yes, yes. Flattery will get you nowhere,” Ito replied with obvious fondness.

Despite myself, I could clearly picture Nishiyama’s playful teasing and Ito’s gentle but exasperated response. It was a scene I witnessed regularly in the club room, so just from their voices alone, I could easily imagine their entire interaction.

“Well, well! Are our drama club’s two biggest stars having a wonderful time?”

There goes Nishiyama again, I thought, recognizing her mischievous tone as she clearly shifted her attention to the other pair.

“N-no, that’s not it, Kazusa-chan. Akira just suddenly…”

“Well, Hinata-chan has such an amazing figure, I couldn’t help feeling a little jealous,” Akira admitted.

“When it comes to amazing figures, Amane is definitely right up there, you know—”

“Kyah! Hey, Kazusa-chan! My towel!”

“Whoa…”

“So beautiful…”

“H-hey, you two, don’t stare at me like that! Kazusa-chan, give me back my towel right now!”

This is… not exactly an ideal situation, I realized with growing dread.

However, if I called out something like “You’re being too loud, please quiet down,” they’d immediately discover I was here. What would happen to me then, having overheard everything up to this point? Wouldn’t that make things incredibly awkward with everyone later?

If I could just slip away quietly, most of these problems would resolve themselves, but there was one significant obstacle—I was currently dealing with a very delicate and sensitive physiological issue.

I’m a healthy guy with an active      imagination. Having inadvertently pictured what was unfolding on the other side until just now, at this particular moment, as a typical male, there were compelling reasons why I couldn’t exactly exit the bath…

Therefore, my only viable option was to quietly cover my ears and wait patiently for time to pass. Time, after all, solves most problems.

That’s what I believed—

“Oh my? You were all here?”

Oh no. The final boss has arrived.

“M-Miyuki-san!” Akira exclaimed.

“Whoa! Miyuki-san, you’re absolutely stunning!” Nishiyama gasped in obvious admiration.

Both Hinata and Nishiyama’s voices carried genuine awe.

Yeah, I can imagine that. And the person who just whispered “How incredible…” in barely audible amazement must have been Ito.

“I’m rather embarrassed appearing like this in front of such young girls…” Miyuki-san said with characteristic modesty.

“M-Mom! Your towel! Please cover yourself properly!”

“Why? It’s just us girls here, isn’t it?”

“Th-that’s not the point!” Akira protested, clearly flustered by her mother’s casual attitude.

I’d never really minded when I went to the bathhouse with my dad, but even though this was the same Miyuki-san I was accustomed to seeing, having her appear in such a state of undress in front of her friends must feel entirely different from Akira’s perspective.

“Um, would it be alright if I touched you a little?” Nishiyama asked with unnecessary boldness.

Miyuki-san seemed completely unbothered. “Please, go right ahead.”

“Fwah! Amazing! It’s so firm but still perfectly soft!”

Is she providing a running commentary for my benefit? That consideration is completely unnecessary for someone hiding in the men’s bath like me— though I had to admit, I was getting a fairly clear picture of the situation.

“Even so, they’ve started to sag recently, and it’s been quite the struggle. After thirty, it became a battle against gravity, but after forty, I’ve been desperately trying to figure out how to disguise it.”

“That’s not true at all! They’re pointing straight up!”

“Hehe, I wonder if that’s the result of massaging them in the bath every day?”

It was then that Hinata, who had been quietly listening until now, spoke up with obvious interest.

“I’d really like to know more about that!”

This surprised me somewhat, though it was certainly a topic that seemed relevant to Hinata’s concerns. Among the four girls, she was probably the one most likely to eventually face her own battle against gravity. Following her, it would probably be Ito, then Nishiyama, and finally Akira… though for some reason, I found myself wanting to cheer for Akira’s future prospects.

No, with Miyuki-san’s genetics, you’ll definitely… no, no, it’s not about size but about shape— if I ever said that aloud, Akira would probably be furious with me, but still.

“I once did makeup for a beauty television show, and a personal trainer taught me about it then. Would you like me to teach you too, Hinata-chan?”

“Yes, please.”

“All right, first, starting from below your collarbone, on the pectoralis major muscle, use your fingers like this—”

“…! Ah, wait, please…”

“Oh my, was that painful?”

“No, it feels good, but having someone else touch me is kind of… Please continue.”

“And then with a clenched fist, slide it in small circular movements—”

“Ah, w-wait, hyah!”

“If you repeat this motion—”

“N-no, that’s, too intense—ah! That spot is sensitive, you can’t! Ah…—”

What exactly is happening over there?

While telling myself I absolutely shouldn’t be listening, I found myself straining to hear every word. I couldn’t help wondering what expressions the other three were making as they watched this scene unfold.

“Wow, so that’s how it’s done…” came a voice filled with fascination.

The person who expressed such admiration was, predictably, Ito. Will      she      remember this technique and practice it herself later?

That was definitely an unnecessary mental intrusion. A completely unnecessary intrusion…

After receiving a comprehensive massage lesson from Miyuki-san, Hinata responded in a voice that sounded like she’d completely melted.

“Th-ank you vewy, vewy much…”

Then Nishiyama eagerly chimed in, “Please do me next!”

“Kazusa-chan, you’re about the same size as me, so I don’t think you really need it…” Akira pointed out with surprising directness.

Oh, nice comeback, Akira!

“But I might need it in the future, right? Besides, Akira-chan, you’ll eventually develop like Miyuki-san, won’t you?”

“R-really? I can still… make it?”

“That’s right! We can still make it!”

“You’re absolutely right! Then I want Mom to teach me too!”

What are you getting convinced for? I mean, the potential is certainly there genetically, but still!

Now, how would Miyuki-san respond? She was probably wearing that characteristic wry smile of hers, but—

“Then shall I teach you two a breast enhancement massage?”

As expected of Miyuki-san.

I see, so that was the alternative approach…

“Please!” both voices chimed in perfect unison.

As if it were the most natural thing in the world, Akira and Nishiyama had taken the bait completely. Competing to be first, Nishiyama called out, “Please start with me!”

“First, just like with Hinata-chan, below the collarbone—”

“Ahyah! Ah, this is, whoa!”

“Oh my, does it tickle?”

“Just a little… but please continue.”

“All right, next, use three fingers to make small circles around the sides for thirty seconds—”

“Wait, this is incredible! Is this really the proper technique?”

“Similarly, use three fingers to make circles around the bottom—”

“Ah, wait, no way! That spot, ah, wait—”

“And then lift upward—”

“Hyahn!”

“And push from the sides toward the center—”

“Wait, Miyuki-sa… that spot, ah…—”

“And for the finishing touch—”

“Nngh~~~~~~~~ !”

“One more push for good measure—”

“Ah, any more is, wait…! Ah, ah, ah…—Ahhhhh~~~~~~~!”

At that moment, for reasons I couldn’t begin to understand, an image of Nishiyama arching backwards in what could only be described as ecstasy flashed unbidden through my mind.

“How was that?”

“Hah… hah… hah…”

“Oh dear, did you get overheated?”

“I’m… f-fine… now…” Nishiyama’s speech had become completely slurred.

Just what kind of massage technique could possibly lead to such a dramatic reaction?

I felt a genuine sense of fear at encountering something so far beyond my comprehension—but still, to think that even that Nishiyama had been completely overwhelmed.

“Okay, next is Akira’s turn, right?”

“No, I think I’m actually fine…” Akira said quickly.

A wise decision, I thought approvingly.

However, if there was one miscalculation in her reasoning—

“It’s perfectly fine. Once you learn the technique, you can practice it yourself from then on—”

It was      her opponent who      none other than that Miyuki-san. She was always gentle and possessed a remarkably flexible personality, but when it came to matters of beauty, she maintained the highest professional standards. She wasn’t the type of person who could be deterred by a simple “I’m actually fine.”

“Wait, Mom, don’t come any closer!”

“It’s fine, it’s fine. Just leave everything to Mama—”

“No, no! Really, I don’t need…! Ahhhhh~~~~~~~…—”

Well, at least it was heartwarming to see this mother and daughter getting along so well.

An involuntary smile began to form on my lips—and just at that moment, the door to the men’s bath was thrown open with considerable force.

“Yo, Ryouta, how’s the water? And hey, why are you grinning all by yourself like that?”

Dad, your timing is absolutely terrible!

“Oh my, Taichi-san? Are you over there?” Miyuki-san’s voice called out sweetly.

“Hm, Miyuki-san? Hey there!” My dad waved cheerfully toward the women’s bath despite being unable to see anything—but I had much bigger problems to worry about.

“Eh? Aniki, you were there this whole time?” Akira’s voice rose in shocked realization.

“I was not!” I protested desperately.

“Yes, you absolutely were!” she shot back with devastating accuracy.

Akira’s furious shout echoed powerfully across the divider.

“Ryouta-senpai, are you really there?” Hinata asked with polite concern.

“Yes, I am…” I admitted reluctantly.

“Why do you answer Hinata-chan so honestly when you just denied it to me!” Akira’s indignation was palpable.

It wasn’t a situation where excuses would help, but I believed that Hinata, at least, would understand the circumstances.

“Majima-senpai! That grin on your face—don’t tell me you were…!” Nishiyama’s voice carried a mixture of horror and accusation.

“You’re completely wrong, Nishiyama!”

“You heard our entire conversation and all those… sounds… didn’t you?” Ito asked with remarkable composure.

“That’s because the acoustics—”

As I struggled to find adequate words, my dad’s expression went completely blank.

“What kind of ‘sounds’ are we talking about here?”

“Dad, just shut up!”

“Why should I?”

After considerable struggling and protests, I found myself facing a tribunal of girls who had been lying in wait for me in the lobby.

＊　＊　＊

“So, I want you to be completely honest,” Nishiyama began, taking the role of chief prosecutor. “Were you listening to everything?”

Her post-bath, naturally flushed skin seemed to turn an even deeper shade of red, clearly demonstrating just how mortified she felt.

“I’ll be completely honest,” I said, hanging my head in genuine contrition. “I was listening. I’m truly sorry…”

When I adopted this thoroughly apologetic posture, Hinata immediately came to my defense. “It’s not your fault, senpai. You couldn’t have known.”

Ito added supportively, “It’s really because we were being too loud,” and didn’t seem particularly disturbed by the situation.

Observing Hinata and Ito’s reasonable reactions, Nishiyama released a long “Haah” sigh.

“…Yeah, you’re right. It’s not like you knew we were right next door, and it’s partly our fault too.”

It seemed Nishiyama understood that the situation wasn’t entirely my responsibility.

“But you’re still angry, aren’t you, Nishiyama…?”

“No, um, I’m just really embarrassed, but I’m not actually angry or anything…” she clarified.

Her demeanor might have suggested anger, but if Nishiyama said otherwise, I’d take her word for it. This was probably her own way of coping with the embarrassment.

“…So, um, Majima-senpai, do you have a moment?” she asked quietly.

“Eh?”

Nishiyama pulled me slightly away from the others and whispered softly near my ear.

“Honestly, did you… Y     ou know… I     magine things while you were listening?”

“Honestly, I did… Y     ou know… I     magine things…” I confessed with complete transparency.

When I gave her that brutally honest reply, Nishiyama’s face turned so intensely red it looked like steam might actually start rising from her head.

“You’re supposed to lie in situations like that! Jeez~~~~~…”

“Er, sorry…”

“…It’s fine, but that ‘voice’ from earlier… just try to forget about it, okay?”

“Got it, I’ll do my absolute best—”

Though truthfully, it would probably echo in my memory for quite some time.

But the person I was most concerned about was—I glanced over at Akira.

She alone maintained a bright red complexion, looking like she desperately wanted to say something but couldn’t find the words.

＊　＊　＊

In the end, we all left Ni-no-yu together as a group.

On the way to our next public bath destination, Akira, who was walking quietly beside me, gently tugged on the sleeve of my yukata with obvious hesitation.

“Aniki, about what happened earlier…”

“Wh-what about it?” I asked, trying to keep my voice steady.

“Um, can I ask you something?”

“What’s wrong?”

Was it something particularly embarrassing and difficult to articulate? Akira curled into herself and turned an absolutely brilliant shade of red.

“My voice earlier… it wasn’t weird, was it…?”

“Weird? What do you mean by that?”

“I mean, it wasn’t very… like me, or rather, how should I put it…”

So that was what Akira had been worrying about. Her tone of voice had been different from usual, and she was apparently mortified that I’d heard it.

“No, it wasn’t weird at all,” I assured her gently.

“Then… what was it like?”

I honestly didn’t want to share my impressions, but she would likely keep asking until I gave her a proper answer, so…

“Well, um… I was a little surprised, but… I guess it did make my heart skip a beat,” I admitted, turning my face away in embarrassment.

I could feel my own face burning bright red, the heat spreading all the way to my ears.

“I see…” she said softly.

“Y-yeah…”

For reasons I couldn’t quite understand, Akira continued walking beside me with her face still that brilliant shade of red for the remainder of our journey.

Incidentally, this is something my dad shared with me later. After emerging from the hot spring, Miyuki-san had apparently remarked with complete innocence,

“Young girls’ skin really is so wonderfully soft and supple, isn’t it~?”

and then laughed in her      completely carefree way     .