The next day, at the medical division.
Kitayama Sho arrived carrying a book under one arm, expecting to be the first one in—instead she found the light already on in the boys’ locker room, wisps of mist curling out from beneath the door.
And.
The mist carried a strange, pungent smell along with it.
She hesitated a moment, then decided to open the door and check.
Oh, good grief.
The instant the door opened, a thick wave of medicinal odor hit her full in the face, sending her into a fit of coughing.
It took her a while to adjust to the sharp smell, and the mist inside was so dense she couldn’t see a hand in front of her face.
Once she’d confirmed the mist wasn’t toxic, she stepped cautiously inside.
“Who’s in here?”
“Anyone?”
She felt her way forward step by step, working through to the bathing area at the back of the locker room, and finally found the source of the mist—
Inside the tub lay a strikingly handsome young boy, stretched out flat on his back in the water, submerged in liquid stained solid black by some kind of medicinal compound.
“Chiba, are you—ow!”
Assuming he’d passed out, she rushed forward, only to catch her foot on something and lose her balance, pitching straight into the tub.
Kitayama Sho held the rank of tokubetsu jōnin, but as a medical-nin she hadn’t sparred or trained her body in years—nowhere near quick enough to catch herself in time.
Splash!
A loud impact, followed immediately by a pained yelp.
“Who’s there?!”
Fortunately the impact had landed on his stomach rather than lower down, or the boy—only just beginning to come into his own, so to speak—would have suffered a genuinely serious injury.
Chiba clutched his stomach and hauled himself out of the tub.
The next moment—
Splash.
“Ptooey, ptooey!”
Kitayama Sho’s head broke the surface, spitting water repeatedly.
Going under headfirst had forced a mouthful of the liquid down her throat, and now her throat burned with a bitter aftertaste.
She coughed hard, gasping for air, her soaked top clinging to a figure that left little to the imagination.
Fortunately, the mist was thick enough that none of it was clearly visible.
“You!
What were you even doing?
I thought you’d passed out!”
Kitayama Sho snapped, thoroughly rattled.
She’d been genuinely terrified a moment ago, too worried to watch her step—and here he was, perfectly fine, brimming with energy, while she was the one who’d ended up—
Her face flushed red.
“Sensei, I was running an experiment.”
Chiba, catching up to the awkwardness of the moment himself, quietly pulled his towel down to cover himself.
“Would you mind stepping out for a moment?”
“…”
Kitayama Sho glanced over once, then silently turned and left.
Unbelievable.
He was just soaking in there the whole time.
She sat outside and switched on the ventilation, letting the mist inside gradually thin out.
Then, glancing down at herself, she didn’t wait for Chiba to emerge—she hurried out at once, only to open the door and find Byakusō standing in the hallway, staring at her, frozen.
“Senior Kitayama?”
“Chiba’s running an experiment in there.
I just—never mind, you’ll understand once you see for yourself.”
Kitayama Sho fled back toward the locker room.
Byakusō hesitated, then walked over and opened the door herself.
A wall of mingled odors hit her at once, and despite years of experience as a medical-nin, she found the smell more than she could stand and shut the door again immediately.
A few minutes later.
Chiba emerged, looking somewhat sheepish.
“There’s no continuous hot water supply at home, so I figured I’d come run the experiment here last night instead.”
“You ran this experiment all night?”
Kitayama Sho stared, incredulous, then flared with irritation.
“Do you have a death wish?
And who runs an experiment like that—using your own body as the test subject?
What if something had gone wrong?”
“It wouldn’t have.
I’d already confirmed the first version was safe—beneficial to the body, if anything, just not especially potent.
What I added in last night’s revision could only affect the potency, not turn it into anything actually toxic.”
Chiba explained himself.
Kitayama Sho wasn’t in any mood to listen.
Every medicine on record had been refined through repeated testing, sure, and credit where due, at least the boy hadn’t thought to test it on anyone but himself.
But.
Treating his own body as expendable test material wasn’t something to shrug off either.
“Sensei, I understand.
That was wrong of me.”
“Understand, do you?”
Kitayama Sho let out something between a laugh and a groan of frustration.
This wasn’t the first time Chiba had pulled something reckless.
The soldier pills had gone the same way—he’d worked the whole thing out quietly on his own and only told her once it was already done.
“Yes, I understand.
I won’t do it again!”
“Sure you won’t.”
Kitayama Sho took a slow breath, forcing her irritation back down.
As for the embarrassing spectacle of tumbling headfirst into the tub, she found she’d stopped caring about that entirely by now.
The office fell quiet for a moment.
“Fine.
I know you’re talented, but talent doesn’t excuse being this careless.
What if you’d actually been poisoned?
Who was going to save you in the middle of the night?”
Kitayama Sho said, her tone settling.
Chiba nodded repeatedly, offering no argument.
That, finally, took the edge off her anger, and the rise and fall beneath her soaked collar settled along with it.
“All right.
Let’s move past this.
What exactly were you experimenting with?”
Kitayama Sho asked, curiosity getting the better of her.
The boy’s talent was extraordinary—short of an S-rank technique, there was nothing he couldn’t master in a handful of attempts, and his creativity ran just as deep.
If she’d scolded him, it was only out of genuine concern for his safety.
Anyone else would have been thrown out of the building by now.
“A medicinal soak.”
“A medicinal soak?”
Kitayama Sho blinked, lost.
What was that supposed to be?
“Put simply, a compound that speeds up muscle recovery and improves the body’s absorption rate, meant to be used while bathing.”
Chiba explained.
Kitayama Sho was a medical-nin, but she’d trained hard enough in her own time to understand exactly what benefit that would offer, the moment he laid it out.
Soldier pills covered stamina.
But.
Muscle fatigue, physical exhaustion—there’d never been a reliable medicinal way to ease that before now.
If Chiba’s compound genuinely worked as described, plenty of shinobi would gladly buy a dose every single day, and that was before factoring in the second benefit—faster absorption meant the body could process and draw on nutrients more efficiently overall.
A medicine built specifically to support training.
“How’s the sourcing on the ingredients?”
Kitayama Sho asked.
Chiba understood what she meant and walked her through the five versions he’d tried.
Versions one and two performed best, but two of the ingredients were rare and hard to source, which meant production would be limited no matter what.
Versions three and four performed noticeably worse, though the two barely differed from each other—their advantage was that the ingredients were common, making both versions easy to substitute and scale.
The final version landed slightly better than three and four, but cost twice as much to produce.
So.
As things stood, none of it was ready to call finished.
Kitayama Sho thought it over.
“Let’s run a wider trial, then.
If you’re willing to split some of the profit, the medical division can help handle the testing.”
“No problem.”
Chiba agreed without a moment’s hesitation.
“You’re sure?
The ingredients might be cheap and the cut modest—maybe ten percent at most—but this is a consumable.
People will keep buying it indefinitely.
Add it all up over time, and that’s real money.”
Kitayama Sho laid the numbers out plainly.
Chiba nodded.
“As long as I have enough to get by, that’s fine.
I’m not particularly interested in money.
Besides, I’ve still got more revisions to make—if I handled every single piece of this myself, when would I have time left to train and study?
I could’ve invented an entire new technique in the time that would take.”
“…”
Damn it.
He’s not even wrong, and somehow that just makes me want to hit him more.
Kitayama Sho thought privately.
She said nothing for a few seconds, then finally: “Bring me a rough proposal tomorrow, and I’ll have Byakusō and the others start testing it.
For now, the most important thing you can do is go home and sleep.
Get some proper rest.”
“Yes, ma’am!”
Chiba stepped out of the office and pulled the door shut behind him, and a moment later heard the muffled thump of a book slamming against the desk from inside.