My Ex-Girlfriend’s Sister Ran Away to My Room, and We Can’t Stop Making Mistakes. - Chapter 1: The First Time.

The First Time.

“Let me stay here. I’ll do anything.”

Those were the words Hachijou Mii greeted me with the moment I opened the door.

It was a bitter night. In the heart of Tokyo, the temperature had dipped toward freezing, the kind of cold that seemed to bite right through you.

Amidst that stinging wind stood Mii, shivering in a short school skirt and a brown duffle coat. She was clutching a suitcase so large it reached her waist. Her black hair had grown since I last saw her; it was a straight, dark curtain that fell all the way to the small of her back.

“You say ‘stay,’ but what about your house?” I asked.

“I left.”

“And school?”

“I’m done with it,” she replied, her expression clouding over.

“…Can I stay?”

“Hold on. The place is a disaster.”

“I don’t care. Thanks.”

Before I could even protest, she was already wheeling her suitcase inside, the rollers rattling against the floor. My home was a cramped, single-room apartment—barely eight mats of living space. Mii took one look at the clutter strewn across the floor and knit her brows in distate.

“Yikes. This place is a dump.”

“I told you it was.”

“Were you drinking?” she asked, her eyes falling on the empty can of happoushu sitting on the table. “I want some too.”

Without waiting for an answer, she helped herself to the fridge, cracked open a fresh can, and began to gulp it down with startling desperation.

“Whoa, hey. You’re a high school girl.”

“I’m not a high school girl anymore. I’m just a minor.”

“Did you drop out?”

“Not officially. But I will.” She wiped the foam from her lips with the back of her hand. “I’m never going back to that house.”

“Never?”

“No. That’s why I need to stay here, Saki-nii.”

“For how long?”

“For a while.”

She let herself fall back onto the bed, then sat up and fixed me with a heavy, unwavering stare.

“Please.”

Hachijou Mii. She was five years younger than me, and she’d been calling me “Saki-nii” for as long as I could remember.

“Is this just some rebellious phase? Look, go home. I’ll give you a ride.”

“I’m not a child anymore.”

“You don’t even have a roof over your head.”

“I’ll leave once I’ve saved up enough money.”

“Listen to me—”

Mii cut me off, her voice firmer than I had ever heard it.

“I’ll do anything.”

She meant it. I could see it in her eyes.

“If you let me stay…”

She spoke the words with a quiet finality, and then she began to slip off her coat.

One by one, she undid the buttons of her uniform. She stepped out of her skirt, revealing a pair of slender, pale legs. Beneath it all, she was wearing a set of pink lingerie.

“You can even have sex with me, Saki-nii.”

That was the day my relationship with Mii became physical.

To put it bluntly, without the flowery prose: I had sex with Mii.

And it was only once we had finally come as one that I realized Mii had been a virgin.