"Welcome to the Lambs' Society," said Yukinoshita Yukino, her voice carrying the calm dignity expected of the club's president.
But unlike her usual tone—clear and sharp like a winter raindrop—today her voice was low and husky, as though she'd been speaking through a sore throat.
Hearing that, Fujiwara Chika's attention immediately shifted from the teacher standing behind her to Yukino herself. Her eyes widened in worry.
"Yukinon, your voice—what happened?"
Before Yukino could answer, another girl seated nearby spoke up. Shinomiya Kaguya, her classmate from Class 1-B, explained in her usual composed tone,
"Yukinoshita-san isn't feeling well today. She came to school despite having a fever."
"Eh? Really?" Chika gasped and rushed over, her expression full of concern. She reached out her hand as if to check Yukino's temperature.
"Did you go to the doctor? What did they say? Is it serious?"
"Honestly, if you're sick, you should be resting," Chika scolded softly. "You're smart enough that missing a few days won't hurt your grades at all, Yukinon."
Yukino gently caught Chika's extended hand and shook her head with a faint smile, signaling that she was fine.
At that moment, Hara Kei, who had been quietly observing, spoke up.
"If Yukinoshita-san isn't feeling well, then today's client reception and questioning should be handled by Fujiwara-san."
He glanced toward the others before continuing,
"In exchange, Yukinoshita-san can take notes. How does that sound?"
"Eh?" Chika blinked in surprise. Kei, usually detached from leadership, suddenly giving out directions was a rare sight. But Yukino simply nodded and moved to comply.
She pulled a notebook labeled "Murder Case Files" from the desk drawer, took out a pen, and positioned herself to record everything precisely.
Kei watched her movements silently, then turned toward the teacher waiting by the door.
Gesturing politely, he invited her into the room.
After pulling a chair over from Yukino's side to sit in front of Chika, he stepped back to his usual seat, returning the stage to the club's self-proclaimed "hostess."
Chika cleared her throat, puffed out her chest slightly, and smiled.
"Welcome to the Lambs' Society! Please tell us about your request!"
"So according to you, the girls' swimming club has been targeted by a phantom thief?" Chika asked curiously, leaning forward.
Her interest was obvious—and not just hers. For teenagers, the word phantom thief carried a mysterious and romantic appeal. Even Kei, Yukino, and Kaguya, who normally kept calm, looked intrigued.
The newcomer wasn't dressed like Shizuka Hiratsuka, their homeroom teacher known for her sharp business suits. Instead, she wore a light sports jacket and long track pants, her tanned skin hinting at someone who spent hours under the sun.
Clearly, she was a P.E. teacher—more specifically, the swimming instructor and the girls' swim team's advisor.
"My name is Zename Saki, but you can just call me Ms. Zename," she began.
Under four attentive gazes, she seemed a little tense at first. But after a brief pause, she exhaled and smiled wryly.
"How should I put it… This whole situation has me completely stumped. My colleagues like to joke that my brain's made of muscle, and honestly, they're probably not wrong." She sighed, then straightened up again with renewed seriousness.
"I heard about how the Lambs' Society helped Mio fulfill her wish. So, if possible, I'd like to ask for your help as well."
She started to bow, but Chika hurriedly stopped her.
Then Ms. Zename began recounting the strange incident.
"When I say phantom thief, I admit—it's just the only word I could think of. Nothing else fits quite right," she said.
"The stolen items are… well, our swim team's swimsuits."
The words dropped like a stone into still water.
Everyone froze. The three girls—Chika, Yukino, and Kaguya—immediately made faces as though they'd just spotted a cockroach.
Noticing their reactions, Ms. Zename frantically waved her hands. "Ah, no, no, it's not what you're thinking! It's not the members' personal swimsuits! Those are all fine!"
"Whew…" Chika sighed in visible relief.
"The ones that disappeared," the teacher continued, "were spares—the unused swimsuits stored in our equipment room. Still sealed, never worn by anyone."
"Huh?"
Everyone looked equally puzzled. Ms. Zename herself seemed no less confused.
"It's November now, and the weather's getting cold," she explained. "We can't use the outdoor pool anymore, so our team's been training indoors. But renting the indoor pool costs a lot more since it needs heating and regular maintenance. Because of that, our budget's gotten tight, and we've had to cut down practice sessions."
Her voice carried a faint note of frustration, but she quickly caught herself, coughed twice, and went back on track.
"The missing swimsuits were stored in the supply room. They were packed inside a large box, along with other sports gear—basketballs, volleyballs, hurdles, high jump mats—probably around a hundred suits in total."
"This morning, when I went to check inventory, the box was still there—but all the swimsuits inside were gone. Every single one."
"Now tell me, what's the point of stealing a bunch of cheap swimsuits? And even if someone wanted to, why not just take the whole box? It would've been easier to move. Why bother opening it and taking only the contents?"
She crossed her arms, frowning deeply.
"If it were just the swimsuits, it might sound trivial—but what if it's a prelude to something bigger? If I just ignore it and something happens later, I'd never forgive myself."
"The whole thing is too strange for me to make sense of… so I came to you."
When she finished, silence filled the room.
Everyone sank into thought.
After a short pause, Chika asked,
"About the storage room key—who has access to it?"
"It's kept in the P.E. office," Ms. Zename replied. "All the P.E. teachers—"
Before she could finish, a sharp ringtone cut through the air.
"Ah, excuse me." She answered the call.
"What?! All right, I'll be right there!"
Hanging up, she shot to her feet, her expression suddenly tense. Without another word, she bolted for the door.
The members of the Lambs' Society exchanged quick looks, then hurried after her.
Her destination: the indoor pool.
But when she threw the door open, she froze.
Floating on the surface of the pool were dozens of dark blue objects.
The others quickly recognized them—swimsuits. The standard, modest one-piece racing suits used for P.E. classes.
And not just that—something dark was also visible beneath the water, scattered across the bottom of the pool. The water was too deep to see clearly what it was.
Hara Kei stepped forward, crouching by the edge. He dipped his fingers into the water.
The moment he felt the temperature, his brows furrowed slightly.
Just then, another pale, slender hand reached forward beside his, brushing the surface of the pool.
He lifted his gaze—
And met a pair of deep, jet-black eyes.
Yukinoshita Yukino's eyes.