My Marriage Partner Seems a Little Off

My name is Katori Nara, and I just received an acceptance letter from a university in Tokyo. My parents, who had been wandering around for years, suddenly came home and told me I had a fiancé.

Before I could even process it, they rushed me off to Tokyo to meet my future husband.

My fiancé was a handsome, wealthy man, noble and refined. He lived alone with his younger sister, an exceptionally beautiful eleven-year-old girl. The first time I saw her, the words "a picture-perfect beauty" sprang to mind. Forgive the expression, but she really was gorgeous.

My fiancé said we could spend some time getting to know each other first, but we had to live together. Looking at his handsome face and the huge mansion behind him, I shamefully found myself tempted. And since his little sister would be living with us too, I thought maybe it wouldn't be so bad.

But things didn't seem to be going the way I'd imagined...

On the first day of living together, I was taking a bath when I spotted the silhouette of his sister outside the frosted glass.

She said, "Can I take a bath with you, big sister?"

Me: "Huh?" What did she mean?

Rika Kihara: "Is that not okay? My nanny used to help me bathe, and now you're here..."

Me: "No, no, of course you can. Come in."

She was this old and still didn't know how to bathe herself. Could she have some kind of psychological problem? Poor thing...

Rika Kihara: "Yay~"

On the seventh day of living together, I returned to my room and found my fiancé and his sister waiting for me. Under the warm yellow light, they both looked toward me. His sister lay under the covers and beckoned me over, while my fiancé read her a bedtime story.

It looked just like a family of three: a daughter and father waiting in bed for their mother.

The image that popped into my head startled me. I didn't actually want to marry this man. I still had to go to school. How could I get married so young?

Absolutely not!

On the thirtieth day of living together, I happened to notice that the door of the cabinet in my fiancé's room could slide open. That night, while they were both out, I opened it. It was pitch-black inside, and I couldn't find the light switch.

Click.

"Looking for this?"

What...

As the room suddenly lit up, I saw...

Them.

*

"You're being naughty, big sister. Didn't we agree you'd wait for us to come home?"

In my daze, I heard his sister say that.

My fiancé chimed in. "Rika, do you want to go first, or should I?"

Go first with what...

What are they doing?!

Why are they taking my clothes off?!

Help! Mr. Ranpo! Didn't you say it was okay to get married?!

So you really are in league with that guy Dazai Osamu!

Atsuko, big sister might be entering the adult world...

1. This is an alternate-universe story based on A Monogamous Marriage. The setting is different, and you don't need to have read the original. There isn't much Bungo Stray Dogs plot, but it does appear, mainly as the heroine's family and friends.

2. Out of character. The timeline is completely different from the original. This story exists purely to bring them together romantically.

3. Taking on the challenge of the perverted Kunikida.

4. It's not started yet! I just want to write this story. The blurb was screenshotted on 2023.09.05.

Theme: Even in the darkness, a flower can bloom facing the blazing sun.