Gloomy Outside, Gal Inside ~Dealing with My Step-Sister Isn't Easy~ - Chapter 01: My Sister with Two Faces

Chapter 01: My Sister with Two Faces

I have a younger sister.

Towards the end of my third year of middle school, my father remarried, giving me a sister who wasn’t related by blood… commonly known as a step-sister. 

While it’s natural for things to feel awkward when a new member suddenly joins the family, I quickly bonded with the woman who is her mother and has become a mother figure to me. However, when it came to my sister, we couldn’t really have any conversations.

“N-nice to meet you… please take care of me.”

My sister… I hate to say it, but she was plain.

With her long, unkempt hair, timid appearance, and a way of speaking that lacked confidence, she was simply a gloomy girl.

However, she had an outstanding figure, to say the least. Her large chest and ample hips were truly remarkable—some of my classmates even commented that it must feel great to hold her. I couldn’t help but feel anxious about that aspect of her.

“Hey, Onii-chan, can you lend me this book?” 

“Onii-chan, the bath is free now.”

“Onii-chan, can you help me with my studies?”

My everyday life with this unfamiliar step-sister gradually became normal without me realizing it. Her appearance didn’t change, and she remained timid in public, even laughing when people called her an introvert at school… but as her brother, I still had my concerns.

“H-hey… Onii-chan!?”

Perhaps it’s something that can only happen between a brother and sister, but there were incidents like when she was still in the bath while I absentmindedly went towards it. 

Fortunately, I didn’t see everything because she had wrapped herself in a bath towel, but there were unexpected happenings like catching a glimpse of the body of a girl around the same age.

“Ah, Onii-chan…”

But… there came a time when I noticed—my sister gradually losing her energy.

No matter how much I asked her what was wrong, she would just pretend everything was fine and not tell me. Our father and mother were also worried, but she didn’t say anything.

“…There must be something going on.”

To me, she was just a step-sister… someone I had recently come to know. 

However, I had already developed a strong sense of responsibility to protect and cherish her as my own little sister, despite not being related by blood. 

Soon I discovered through one of her close friends without my sister knowing that she was being bullied.

My actions were swift from that point on.

I wasted no time in explaining the situation to our father and mother, and together with my sister’s friends, we gathered all the evidence of the bullying, including the evidence that the homeroom teacher had been attempting to conceal.

“I’m sorry… I was scared… I’m sorry!”

Her friend apologized for not being able to do anything.

I understood her feelings of not wanting to become the target of bullying herself, but I was about to complain that she could have at least informed someone like me, an external person related to the school. However, I couldn’t speak harshly to a girl younger than me.

“Onii-chan… why?”

Why? It should be obvious.

An older brother is supposed to protect his sister—especially when we finally start getting along and can have normal conversations at home. Though I initially thought she was plain, I shouldn’t underestimate how I find myself foolishly praising my sister in my mind, repeating how cute she is when I see her unexpectedly well-structured face.

“I have things I want to say, like why you kept silent. But… it’s okay now — it’s all okay. No matter what happens, I will protect you.”

That may have just been an act of bravado.

However, it also serves as a reminder to myself for not noticing the changes my sister had been enduring all along… She surely didn’t wish for things to go that far. 

But from that moment on, I strongly desired to protect her.

“Uu… Uun…”

Realizing that she no longer had to endure, that there was someone reliable she could rely on… someone who would protect her, my sister continued to cry in my embrace for a while.

Afterwards, in order to dedicate time to the healing of her heart, my sister transitioned to remote learning.

Perhaps because the high school I was aiming for at the time was relatively prestigious in terms of its entrance exam score, my sister also began studying hard to attend that school… and her efforts paid off. She became a student at the same high school as me.

However… is this still a normal, good story?

It may sound conceited to say it myself, but I truly think it’s a good story… However, the problem arises from here—since the day I helped her, I started receiving strange looks, and she began coming to my room more often, with a significant increase in physical contact.

And now, in my second year of high school while she’s in her first year… I found myself enduring various challenges on a daily basis.

▼▽

“Nii-san…? Are you awake? Nii~san?”

I heard my sister’s voice waking me up in the morning. I’m still sleepy… I want to keep sleeping, so I curled up my body as if to hide under the covers.

“Mou… It’s a day off today, you know? I bet you were playing games until late.”

Correct… Last night, I played an online game with my friends for hours.

That’s why I’m sleepy. And she did say it’s a holiday… so let me sleep more, please, I beg you.

While I was thinking that, I felt my sister’s presence bending down next to me.

“If you won’t wake up no matter what… I might play a prank on you, you know~?”

Just as I thought she was creating a gap in the blanket, my sister sneaked in, covering herself with the same blanket.

The sweet scent of citrus tickled my nostrils, and when I opened my eyes, I was greeted by the lovely face of a girl.

“Good morning, Nii-san♪”

“Good morning… Miu.”

Even in the darkness, I could see her face clearly. After exchanging glances with her for a while, I sighed and reluctantly sat up.

“Geez, it’s a day off, right?”

“So what? I want to spend time with my Nii-san!”

“…”

“Nishishi(giggle). I know you don’t mind, Nii-san.”

Hearing her hit the nail on the head, I let out another sigh.

Despite wearing a short skirt, my stepsister Miu Kuon was sitting cross-legged in front of me, inadvertently exposing her strawberry-patterned panties.

Her bright dyed hair, well-defined features, confident and provocative expression… and her outfit that reveals cleavage, making it hard to look away. It’s an incredibly eye-catching attire.

“You’re such a perv, Nii-san, peeking at your little sister’s chest♪” 

“But you’re the one showing it off!” 

“Oh, did I get caught?”

However… I feel really embarrassed, my face turning red.

Looking at Miu, who is grinning in front of me, it’s clear that she finds this exchange enjoyable in itself. There are many thoughts that cross my mind when I see her like this.

How did she end up like this?

(…It started after entering high school. Miu became like this.)

Originally, Miu was a very plain girl.

However, with the start of high school, she underwent a complete transformation from a plain appearance to a stylish beauty. But this side of her is not shown at school.

She only takes on this different appearance at home… in other words, only in front of me and our parents.

“Hey, Nii-san, let’s go on a date. You’re free anyway, right?”

“Well, I guess so.”

As a high school student now, Miu doesn’t experience bullying like she did in middle school. 

However, since she still dresses modestly outside, she naturally doesn’t have a boyfriend, and her circle of friends at school is limited. 

Nevertheless, she finds it entertaining to fully embrace this different side of herself, often posting selfies on Twitter and enjoying the reactions.

“…Haah.”

I let out another deep sigh.

Ever since I helped her, our physical contact has increased significantly, or rather, the distance between us has become much closer.

While our parents find our close relationship heartwarming, the many actions that come from a dynamite-bodied girl like Miu to an adolescent boy like me can be quite unsettling for my heart.

“Miu, I’m going to change, so get out of here.”

“Huh? It’s fine, I won’t look.”

“Just go outside!”

My sister is dear to me… and she’s so cute, with a great figure that makes my heart race.

Her personality is great too, and she has been rapidly improving her cooking skills recently under our mother’s guidance. If she were to have a boyfriend, he would be fortunate.

With such a sister who has two different sides, one in public and one in private, I have been subjected to teasing since this year.

“Alright!”

I give my cheeks a gentle pat, steeling myself for what’s to come.

Once again today, I’ll dedicate the entire day to being with my sister… that’s my unwavering decision as Ayato Kuon, her big brother.

Yet, there’s one concern weighing on my mind.

Lately, I catch myself having inappropriate thoughts when I look at my sister… It’s a troubling situation, and I sincerely feel a sense of urgency about it.

[Postscript]

For now, I will release what I have been holding back and write it down. 

With a fresh start, I will do my best.