The Case Where I Found Out My Big Sister with a Brother Complex Was Actually My Stepsister, Tried to Hide It, but She Found Out Immediately and Became Uncontrollable - 1

Chapter 1: My Big Sister’s Dream

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“Tsumugu~!”

As soon as I got home, the one who greeted me by calling my name—Tsumugu Tsunagi—was not my girlfriend… but my big sister. With long black hair, well-defined features, and a figure that had all the right curves in all the right places, she was a beautiful woman named Nozomi Tsunagi—my big sister.

“Welcome back. You’re home late today, huh?”

“I was hanging out with a friend.”

“I see. Spending time with your friend is a good thing… Dinner’s almost ready. Do you want to eat right away? Or would you rather take a bath first?”

“If the food is almost ready, I’d like to eat while it’s still hot, so I’ll have dinner first.”

“When did you get so good at choosing your words~? You don’t go saying stuff like that to girls in your class… Right?”

Only the last part was said in a quieter, ominous tone.

“I don’t.”

“Well, that’s good to hear~!”

With a cheerful smile, Nee-san walked past the living room toward the kitchen. There was no way I’d ever get the chance to have a classmate cook for me, let alone a girl my age. It was highly unlikely I would get the chance to say something like that to someone other than my Nee-san. 

Just what’s gotten into her all of a sudden?

As I wondered about that, I took off my shoes, stepped into the entryway, and waited in the living room while Nee-san finished cooking. About five minutes later—

“We’re having curry rice today~”

“Thanks.”

We sat at the same table and began eating the curry rice together.

“How’s the curry rice? Is it good?”

“Yeah. Thanks, Nee-san.”

Nee-san was, in general, a high-spec person. Whether it was academics, sports, or housework, there was nothing to criticize about her. If I had to point out one thing, it would be that even as a third-year high school student, she still hadn’t outgrown being attached to her little brother. But that wasn’t necessarily a bad thing—in fact, it was better than being distant, and if anything, it showed how much she cared for her little brother.

“…I wish I were the same age as you, Tsumugu. That way, we could graduate high school together. Maybe I should repeat a year.”

“That’s an even more outrageous thing to say than usual. I hope someone nice shows up for you soon, Nee-san.”

Because she was always acting like this, a part of me was worried she wouldn’t be able to graduate from her attachment to her little brother. That said, Nee-san’s happiness came first. People probably picture different things when they heard the word “happiness,” but for me happiness meant living happily with someone you enjoy being with. But when I said that out loud, somehow Nee-san’s expression turned a bit gloomy. 

“Nee-san?”

“…Even when I know I have to change, it’s not easy for people to actually change, is it? Even when I know I shouldn’t wish for something… Before I know it, I end up wishing for it anyway.”

“Wishing…?”

“I’ve kept it a secret until now, but… Onee-chan’s dream… I’ll tell you, just you, Tsumugu… You might be shocked to hear this, though.”

“If it’s your dream, there’s no way I wouldn’t support it. What is it?”

“…My dream is to be happy together with you, Tsumugu.”

She placed a hand over her chest as she said that. That alone told me just how important that dream was to her.

“I know from the start it’s a dream that could never come true, though.”

She said that with a sorrowful look on her face. A dream that could never come true…? Her words left me puzzled. Why couldn’t it come true? There was a good chance we could have a happy future together though.

“I think there’s plenty of possibility for us to be happy together. So let’s not be so pessimistic and just work through life together… We’re siblings, after all.”

“…Yeah, you’re right.”

She smiled, but that smile carried a trace of resignation.

“Sorry, okay? I made things awkward because of me. You said the curry rice was delicious, so we better eat it before it gets cold.”

“Ah, yeah.”

After that, the atmosphere returned to normal, and the two of us finished our delicious curry rice while chatting happily. While we were cleaning up the dishes, Nee-san spoke to me in a quiet voice.

“Tsumugu… I’ll do my best as your big sister. So if anything ever happens, don’t hesitate to rely on me… I’ll be your dependable big sister, okay?”

“You don’t have to say it. I’ve always relied on you, Nee-san.”

“…Yeah.”

Then, after we finished everything we needed to do, we went to sleep. Nee-san was acting a little strange today, but I guess people could be a bit weird sometimes. 

I’m sure Nee-san is going to be back to normal when morning comes…

“Come on, come on! Let me tie your necktie for you!”

“I-It’s fine! I can do it myself! Also, you’re way too close!”

“We’re family, you know! Real siblings! We only have each other, so there’s no need for you to worry about anything!”

Even through her clothes, the size of Nee-san’s chest was impossible to ignore as she pressed it against me without hesitation and began tying my uniform’s necktie. I was glad things were back to normal… But maybe they were too back to normal. I didn’t have any impure thoughts toward my blood-related sister, but as a second-year high school student in the peak of adolescence, I still had some desires I couldn’t completely suppress.

If Nee-san hadn’t been my blood-related sister, I honestly didn’t know what kind of emotions I would be feeling right now. In a way, maybe it was a good thing we were blood-related. Because if we weren’t… Then I—

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