Manaka found herself spending her days in a state of frustration.
She had teased Ryosuke, but she never expected him to actually make a move—and yet, the next morning, he acted as if nothing had happened.
"Marin, eat your tomatoes too."
"... Yes, Nii-san."
After coaxing her vegetable-averse sister to finish her salad, Manaka finished her own morning preparations and left the house.
"Nee-san, hurry up! You'll be late."
"I-I know."
The voice coming from his well-shaped lips seemed to be taunting her now. But at the same time—
...After what he did...
She felt a surge of irritation. She knew he had a girlfriend. And he was calling her "Nii-san" and acting all sweet—
She wanted to confront him about his intentions, but when she caught up to him on his way to school—
"Hey, Ryosuke, about yesterday—"
"Yesterday? Oh, the pot-au-feu for dinner? Nee-san asked for seconds, didn't she? But tonight's menu is already set."
"Hey—"
"...Nee-san. How far are you going to follow me? Your school isn't even this way. Do you really want to be with me that badly?"
"Ugh... Listen!"
"See you tonight."
With an unnerving calmness, he sauntered off.
*****
Even at school, that uneasy feeling lingered. During lunch break, lost in thought, Takuma leaned forward from his seat in front of me and peered at my face.
"What's wrong, Manaka? Troubled by something?"
True to form for childhood friends, he immediately noticed the change in my expression.
"Huh? No..."
My words caught in my throat.
Last night, I'd kissed another boy—my stepbrother, the one I lived with. There was no way I could tell Takuma about it—not even him, especially not him.
"It's nothing. Anyway... can I go to your place today, Takuma?"
"Sure, that's fine," Takuma said with a grin.
Inside, Manaka felt a wave of relief, but it was accompanied by an unprecedented sense of guilt.
It had become an unspoken understanding between them—every after-school date ended with sex. Being held by him would surely blow away all these feelings.
I'll be home late... I should text Marin.
She wanted to be loved by her childhood friend as soon as possible.
Distracted by these thoughts, Manaka couldn't focus on her afternoon classes.
*****
"I'm home!"
Manaka returned to the Shito residence with light steps.
The lingering sensations from her time with Takuma still clung to her skin, as hot as the summer sunset—making it seem like her troubled moments had never existed.
All of it was thanks to Takuma.
They had loved each other completely in his room, whispering about their future. That precious time had erased all her worries.
I felt bad for getting home late and making my younger brother cook dinner for me. I decided to just apologize.
"Ryosuke, Marin—"
As I entered the living room, now so familiar to me...
Sure enough, my younger brother and sister had already finished eating. With our parents still out, the two of them were spending time together in the empty room. They were seated on the sofa, watching some kind of dating reality show on the big wall-mounted TV.
That's fine. That's fine, but—
"This guy's lying."
"Yeah. Everyone's acting, of course, but he's taken it beyond just acting. He's actually deceiving the other contestants. He's really good at handling eye contact."
"And the timing of his lines is impeccable. He's reading his opponents' breathing and speaking at just the right moment."
"This is educational."
It wasn't just that they were watching the show more like observers than viewers—what really confused Manaka was that they were holding each other. Ryosuke was sitting deeply on the sofa, and Marin was sitting on his lap, clinging to his neck.
"Ah, welcome home, Nee-san."
"Welcome back."
When they turned around, neither showed any sign of being flustered. Ryosuke, of course, possessed extraordinary handsomeness, and my younger sister, Marin, was no less strikingly beautiful. The two of them standing in a "princess carry" pose made for an almost too picture-perfect scene.
"Y-you two, what are you...?"
Just recently, the two had been barely on speaking terms, and Marin had even harbored hostility toward him. This sudden closeness was highly abnormal.
Marin—someone who had never acted so clingy even with our mother or Manaka—was now completely dependent on Ryosuke, a man, as she leaned into him.
"Supper's ready. Sorry, but could you heat it up yourself?"
Ryosuke's gaze immediately returned to the screen.
(...)
The unspoken message—that he should pay more attention to his younger sister—made his chest churn. Just last night, she had even kissed him. He'd even declared to Manaka that he was aroused by her as a man.
To have all that treated as if it never happened... it felt like a deep wound to Manaka's feminine pride—the self-esteem Takuma had helped her build.
"Hey, Ryosuke. Come here for a minute."
"But I'm in the middle of something!"
"Never mind that! Just come!"
Ryosuke stood up with an exasperated sigh.
"Nii-san. Please come back soon."
As Ryosuke followed Manaka out of the living room, Marin's overly sweet voice lingered in his ears.
*****
"Hey. What was that about earlier?"
"What do you mean?"
I cornered Ryosuke in the same hallway on the second floor as yesterday.
"You didn't... do something to Marin, did you?"
Her clinginess was abnormal. Marin, who usually never let anyone get close to her, was now initiating physical contact and acting so affectionate.
They're just teenagers. It's understandable for a girl to be attracted to an older boy she feels close to for the first time, and it's natural to find that endearing.
"Technically, we're siblings."
"Technically, yes."
Ryosuke's dismissive snort was irritating.
"Anyway, what misunderstanding are you having, Sis? I didn't do anything. Like I'd do anything inappropriate to my younger sister."
"But last night—"
"You mean the kiss?"
Ryosuke stated it so shamelessly, without a hint of embarrassment.
"That was just because you're my older sister."
"!! What kind of line is that? Did you learn that from that video earlier?"
I tried to hide my emotions by speaking sharply, but I couldn't completely mask my shock.
"You think I don't notice? You two have sex every day."
"What—?"
"No, you knew, didn't you? From the day Nii-san first came to our house... right here in this room."
"Ryosuke—?!"
As he spoke, his younger brother shoved Manaka into her room, pressing her against the wall.
He knew? From the very beginning...?!
Manaka and her lover had been holed up in this room together, and she'd half-expected the impressionable Ryosuke to notice—though the thrill of that possibility had secretly delighted her.
Still, she never dreamed he'd actually mention that day, the day Takuma first took her in this very room.
"Ugh!"
Ryosuke's grip on her right wrist hurt. Despite being about the same height and built more slenderly than her, his fingers were surprisingly strong. She realized he was a man too—a man she shouldn't have provoked so carelessly.
"Ugh?! Mmm?! Ryosuke...?!"
My lips were stolen again, and I was pushed down onto the bed. The impact felt like the world was turning upside down. Ryosuke's face filled my vision. He looked down at me with an infuriatingly calm smile. Then he kissed me repeatedly, over and over, while I was pinned to the bed.
His arms skillfully restrained my struggles as his hands roamed my body.
"S-stop it! You're going too far! This isn't a joke anymore—! Ah!"
I tried to scold him like the older sister I was, but I couldn't muster any dignity.
His fingers were frighteningly strong, yet they touched my softest places with surprising tenderness. He stroked my breasts through my uniform blouse, ignoring the bra's stiffness to flick my nipples with pinpoint accuracy.
"Ugh?! Ah, huh...?!"
His fingers teased me with practiced precision, the exact right pressure—like I was pleasuring myself.
"S-stop! Stop it right now...!"
I should be terrified and furious to be assaulted like this, but instead of pain, all Ryosuke gave me was an overwhelming, irresistible wave of pleasure.
If I screamed, Marin might come running, but I couldn't let her see me like this. Even though she acted grown-up, she was still just a kid. How could I let my younger sister witness her older brother and sister-in-law entangled in bed? I couldn't bear the thought of the neighbors hearing.
If only Takuma were here right now... But now, I had to reject Ryosuke on my own.
"I'm serious, I'll get angry...! Mmmph?! Mmm, mmm...!"
His tongue forced its way into my mouth, sliding in slickly. Where had my younger brother even learned this? His tongue glided smoothly over the inside of my mouth.
Normally, forced intimacy—mucous membrane contact, saliva exchange—would be utterly repulsive. Yet being kissed by Ryosuke felt like having aphrodisiac directly injected into my bloodstream, eroding my rational thought.
My blouse was stripped off, exposing my undergarments. My sweat-drenched, tender skin was now at Ryosuke's mercy.
"No! Ah! Agh!"
Fingers slipped through the gap in my bra, flicking my nipple. A jolt of electric-like pleasure shot from my shamefully erect nipple, making my lower body twitch violently.
No, this can't be happening...!
I couldn't believe I was being violated by my own younger brother. It felt utterly unreal. Even when I tried to kick my legs, Ryosuke pinned them down, rendering me immobile.
Despair, humiliation, and regret scrambled my thoughts into a chaotic mess.