Kirisu Miharu was naturally not a lovesick girl.
The reason she had been so thoroughly undone by Hozuki Nozomi's smile—caught between confusion and a daze that prickled heat across her cheeks—was primarily the product of near-zero experience dealing with men. Her impression of boys existed only in the pages of light novels: brooding heroes with tragic backstories, charming princes who appeared at opportune moments to sweep heroines off their feet. Abstract concepts. Safe, two-dimensional fantasies.
She had no experience interacting with real boys in any normal capacity.
Furthermore, the person she most admired in this world was the former figure skating queen—her own Nee-san, Kirisu Mafuyu!
To follow in her Nee-san's graceful footsteps, Miharu herself had become an amateur figure skater, spending countless hours on cold rinks, chasing that same elegant perfection.
"Please have a seat. Would you like something to drink?"
Hozuki Nozomi, acting like a host, moved with easy familiarity toward the water dispenser tucked beside the kitchen doorway. He retrieved a cup from the cabinet beneath it without even looking—muscle memory guiding his hand to the exact shelf—and turned back to her with that same disarming smile.
"En, I'll have some." Miharu nodded, settling onto the plush sofa.
But something snagged in her mind almost immediately.
Wait.
Wasn't he Nee-san's student?
Why was he acting like the master of this house?
And he'd taken out those cups so skillfully! Like he'd done it a hundred times before!
Miharu's mind buzzed like a struck tuning fork. A word that made blood rush to her face and her heart pound against her ribs appeared unbidden:
Cohabitation!
Could it be that Nee-san and this boy were... a couple? In a relationship?
Had Nee-san and Hozuki Nozomi already started cohabiting?
The thought sent ice through her veins. Immediately, Miharu's expression shifted—wariness replacing her earlier flustered confusion. She stared at him with narrowed eyes.
She absolutely would not allow her perfect, pure Nee-san to be defiled—or worse, taken away—by some boy!
"Are you really Nee-san's student?"
"Of course. Genuine article." Nozomi's voice remained calm, almost amused. He reached into his pocket and withdrew a laminated card. "Here's my student ID, Miss Miharu. Please take a look."
She snatched it from his fingers.
SOUBU HIGH SCHOOL — FIRST YEAR
The photograph showed his face clearly—those same handsome features, that same irritatingly confident expression.
Her face reddened further. Oh no.
He really was a student. A first-year student.
Nee-san , she thought desperately, even if you find a boyfriend, you can't find someone so much younger than you! Teacher-student relationships are wrong!
However...
She glanced up at him again. The afternoon light caught the sharp line of his jaw, the easy confidence in his posture as he stood there—tall, lean, infuriatingly composed. His dark hair fell just slightly into his eyes, and when he tilted his head with that questioning look, something fluttered traitorously in her chest.
He really is quite handsome...
But no!
Miharu crushed that thought ruthlessly. Her gaze hardened with renewed determination. She would not allow her Nee-san to be taken away by anyone!
It's decided.
I, Kirisu Miharu, will firmly oppose him dating Nee-san!
Even if it means sacrificing myself, I must protect my Nee-san's purity!
Hozuki Nozomi, of course, had no idea what dramatic resolutions were unfolding behind those dark eyes.
If he had known—if he'd glimpsed even a fraction of the "sacrifice herself" clause in Miharu's internal declaration—he would have acted without hesitation. Spoken up. Taken everything offered and more.
But he remained blissfully oblivious.
Having made up her mind, Miharu tried to compose herself. The expression she arranged on her face was... not quite right. She widened her eyes deliberately, attempted something that might have been a wink, and stretched her lips into what she imagined was a seductive smile.
The result looked more like she was experiencing mild facial paralysis.
"Um, Nozomi-san, what do you think of my Nee-san?"
"En? You're asking my opinion of Teacher Mafuyu?" He considered for a moment, then smiled. "Well—she's super cute, of course."
"That's right! Nee-san is the cutest!" Miharu's eyes lit up immediately, instinctive agreement overriding her earlier suspicion.
Then she remembered her mission. She winked again—that same strained, squinting expression—and tried for another awkward smile.
"Um... then what do you think of me?"
"You?"
Nozomi's gaze traveled over her with frank assessment.
Kirisu Miharu was naturally a beautiful girl—that much was immediately apparent. As Kirisu Mafuyu's younger sister, she couldn't be anything less. Her features carried the same delicate bone structure, the same graceful proportions, though rendered in a slightly softer, more youthful key.
She was smaller than her sister—shorter by perhaps ten centimeters, her chest modestly filling the front of her light sweater rather than straining against fabric the way Mafuyu's curves did. But in other aspects, she matched her sister's beauty entirely.
A slender, petite frame with the toned grace of a figure skater—narrow waist curving into slim hips, legs that seemed impossibly long for her height. Her skin held that porcelain fairness common to both sisters, smooth and unblemished. Pink hair spilled past her shoulders in loose waves, framing a face that still carried hints of girlish softness—round cheeks, full lips, large eyes that dominated her delicate features.
She practically radiated youthful energy.
Nozomi's lips curved appreciatively. "Miss Miharu is naturally also a very cute girl. After all, you are Teacher Mafuyu's sister."
Miharu beamed at the praise, her eyebrows and eyes curving into a genuine smile—this one far more natural and pleasing than her earlier attempts at whatever she'd been doing with her face.
That wasn't seduction , Nozomi thought with mild amusement. That was just making funny faces.
This girl clearly had no idea how to entice boys. None whatsoever.
Miharu's brightened mood lasted exactly one second before she remembered her purpose. She took a deep breath, squaring her small shoulders, and fixed him with a determined stare.
"Nozomi-san. I have to ask you something directly."
"Go ahead."
"You didn't do anything strange to my sister, did you?"
"Uh..." Nozomi blinked. "What's 'strange'?"
"It's... it's..." Her face flushed crimson. "It's that kind of thing! After a boy and a girl start dating!"
Oh.
Understanding dawned. "Of course not. Why would you ask me something like that?"
"This... I..." Miharu fumbled for words.
Before she could continue, the sound of the front door opening cut through the apartment.
"I'm home."
Kirisu Mafuyu's voice drifted in from the entryway, followed by the rustle of shopping bags.
"Nozomi! Come help me with the groceries—they're so heavy."
"Okay, I'm coming right now."
He rose from his seat and moved toward the entrance. Mafuyu stood there—pink hair slightly windswept, cheeks flushed from the walk home, arms laden with bulging plastic bags that strained against the weight of vegetables and meat. She had changed into a simple cream blouse earlier, the fabric stretching pleasantly across her generous chest as she struggled with her burden.
She handed him the groceries—their fingers brushing briefly—and then froze as her gaze landed on the figure sitting on her sofa.
"Oh! Miharu? Why are you here?"
"Hehe! Because I missed you, Nee-san!"
Miharu abandoned all pretense of interrogation. She bounded off the sofa and threw herself into her sister's arms, burying her face against that soft, ample chest and rubbing her cheek against the yielding warmth like a contented cat.
My school is off today, so I came to see you~
Nozomi watched this display with undisguised envy. His lips pressed into a subtle pout.
I want to rub too...
But cooking came first.
Mafuyu awkwardly pushed her clingy sister back a step, a flush creeping up her neck. She glanced at Nozomi, something unspoken passing between them.
"Um, Nozomi, this is my younger sister Miharu. You go to the kitchen first—I'll be there in a moment."
"Oh."
He shrugged, didn't ask questions, and carried the groceries past the counter and into the small kitchen space.
He understood perfectly.
Mafuyu didn't want her sister to discover her domestic incompetence—the burnt dishes, the failed attempts at simple recipes, the apartment that would descend into chaos without his intervention. In Miharu's eyes, Nee-san was omnipotent. Perfect. An untouchable idol.
That carefully constructed image absolutely could not be allowed to crumble.
---
The moment Nozomi disappeared into the kitchen, Miharu seized her sister's wrist and dragged her to the sofa.
"Nee-san," she hissed urgently. "Honestly—what's your relationship with Hozuki Nozomi? You two aren't living together, are you? For how long?"
She's suspicious, Mafuyu thought, heat flooding her cheeks. Oh god, she thinks we're—
"What are you talking about?" Her voice came out too high. "I'm not living with him!"
"Huh? You're not?" Miharu's brow furrowed. "But he's so skilled at getting drinks, and he seems so familiar with this place..."
"Ahem, well—actually—"
Mafuyu scrambled for an explanation that wouldn't shatter her perfect-sister image.
"He was slacking off in class and I caught him. He's also helped me out a few times, so to tutor him, I occasionally let him come over and sit. And—incidentally—I punish him by having him clean for me."
Miharu stared.
What?
He helped her... and she punished him?
Could this be some special play between them?
The younger sister's imagination spiraled into dangerous territory. Her gaze hardened with renewed determination.
I absolutely must protect Nee-san's purity!
"Ahem, well—Miharu, you sit for a bit." Mafuyu rose quickly, smoothing her skirt. "Since you're here, let's have dinner together later."
"Okay!" Miharu's suspicious expression melted into eager anticipation. "Nee-san's cooking—I'm really looking forward to it!"
Mafuyu's smile turned brittle.
It's over, she thought desperately, already backing toward the kitchen. If Miharu eats my actual cooking, Nee-san's image will collapse completely!
She slipped through the kitchen doorway, the scent of sesame oil and ginger already rising from where Nozomi had begun preparations.
Fortunately—fortunately—Hozuki Nozomi had been invited over today.