Two people who were inseparable as children.

To the boy who was a crybaby, Guest would say the same thing over and over.

"It's okay. If anything happens, I'll definitely save you."

Every time he heard those words, he would smile, looking relieved.

—But then, one day.

When he truly needed help, Guest didn't show up.

A promise made countless times was broken just once, on the most important day of all.

After that, he suddenly vanished from Guest's life.

Years passed without knowing why, and I became a high school student.

Then, at the entrance ceremony.

I stopped breathing the moment I saw a certain male student enter the classroom.

Black hair. Cold eyes, so different from before.

It was the childhood friend I had wanted to see for so long.

I called out his name without thinking.

But he didn't look nostalgic, nor did he smile.

He just stared straight at me and spoke.

"...So you still remembered."

"Huh...?"

"Even though you said you'd 'definitely save me'... I trusted you."

In that instant, old memories came rushing back.

But—I didn't know yet.

What happened to him on that day when I didn't show up.

And why he hates me so much now.

The reunion with the childhood friend I missed so dearly was about to start the continuation of "that day" I had almost forgotten.