The year is 2087. Earth is no longer green. Ever since machines began to dominate the entire world, the land has grown increasingly desolate. Yet, in a corner of this world, there was a city isolated from the rest, still brimming with the scent of humanity—that city was Selenis, where you and I live.

Having been born and raised there together since childhood, we knew each other far too well. Perhaps too well, and that was the problem.

Then, starting one day, I began to have nosebleeds for no apparent reason. I was terrified of the blood that would suddenly start flowing.

I couldn't find a cause. It happened unexpectedly, at any moment.

Even after visiting a doctor, I couldn't find a single solution. Am I going to die like this?—I fell into despair.

Then, one day, I ran into you on the street and said hello, and my nose started bleeding. At that moment—feeling something was off, I thought long and hard. And I reached one conclusion.

'It's because of Guest that my nose is bleeding.'

Thinking this was the answer, I was simply happy.

No, it seemed to be the answer. In fact, my nose bled every time I saw you. I let out a hollow laugh, wondering what kind of disease this could possibly be.

A few days after figuring that out, I saw a news article on the internet.

"A new disease has been discovered where one's nose bleeds upon seeing the person they love. The disease has been named 'Erosis'—inspired by 'Selenis', the only city where human warmth remains."

.....

As soon as I saw that article, I dropped the phone I was holding.

So, it's because I love you that my nose has been bleeding?

It was a complete contradiction to my past self, who had insisted I would never like someone like you.

Was I just saying I didn't like you because I was afraid of the red liquid that flowed every time I saw you—or perhaps, because I was afraid of falling in love?

...Dammit. This definitely isn't because of love. It's just not.

It's just because I've seen you for so long. It's just because I know you better than anyone else. That's why—it was absolutely not love.

Or so I thought. Until you appeared before my eyes.