Even breathing felt like a sin against someone else. In the corner of a square room submerged in darkness, I sit huddled, holding my knees and holding my breath. What churns in the back of my mind are irreversible mistakes and an erasable sense of guilt. The thought that I might have destroyed someone's life, that my very existence here might be a mistake—every time these thoughts swirl, a searing pain tortures the depths of my chest. I want to disappear. I wish I could just be painted over, along with my existence, leaving no trace in this world. Just as a small sigh escaped my dry lips, crushed by despair—

The screen of the smartphone resting on my knees quietly emitted a faint light. A notification popped up in the darkness. As I instinctively looked down, the music player on the screen displayed a title I didn't recognize.

"Untitled"

A sterile track that hadn't even been given a name. I didn't remember installing the app, nor did I have any memory of saving such a song. Frowning at the eeriness, I reached out to turn off the screen. But—why? In the suffocating air of this room, those white letters drew me in so strongly, as if they were calling to me, and wouldn't let go. It's not like I have anything left to lose anyway. Pushed by a feeling close to self-abandonment, my fingertip touched the play button on the screen as if pulled by a magnet. In the next moment, there was no sound. Instead, what overflowed was a blinding, pure white light.

"—!?"

The light overflowing from the smartphone screen instantly swallowed my vision, erasing the scenery of the room. A sensation of floating and intense dizziness struck me, and in a feeling as if gravity itself had been lost, my consciousness rapidly fell into a deep, deep darkness.

...Poke, poke.

In the freezing air, I felt something soft touch my right cheek. ...Poke, poke...

A sensation of being lightly prodded in a steady, rhythmic beat.

"...Nn..."

I slowly lifted my heavy eyelids. The first thing I saw was a colorless white and gray sky. And the figure of a girl peering into my face. Layered, pale gray hair. Heterochromatic eyes of faint red and blue, and a quiet, somewhat hollow expression. She poked my cheek again with her small fingertip.

Miku: "...Oh, you're awake."

A small, whispering voice. I hurriedly sat up and looked around. This was not the cramped room I knew. A vast space without color or sound, stretching to the horizon. Things like torn cloth swayed even though there was no wind, and countless triangular objects floated in the air. Where is this? Just a moment ago, I was in my room—.

Miku: "This is... the Empty Sekai."

While staring back at my confused self, the girl quietly continued.

Miku: "I am Miku. ...I've been waiting for you."