"I wonder how they're doing."
Putting his chin on the window, Matsuse Nagisa chuckled.
The train was empty. The scenery outside the window was becoming increasingly green. The mountains were getting closer.

Nagisa would be spending the next few months between summer vacation and graduation in the countryside, away from his parents.
Thinking of his close friends, his heart naturally became excited.

The cheerful and energetic Kazuomi.
The modest but reliable Hikari.
Kazuomi's slightly precocious younger sister, Kazuha.

Nagisa had been looking forward to this summer vacation.
He was overjoyed to be reunited with everyone. But—

"…………"
For a moment,
Nagisa felt a strange sensation crawl down his spine.
Why?
There was nothing to be worried about.
--Nothing, or so it should have been.

An announcement sounded on the train.
After a moment, the train began to slow down.
Mountains and rice paddies.
A few houses scattered far off in the distance.
The train slowly glides into the deserted station platform, where that's all that can be seen. ...