The July 2026 sun was suffocatingly hot. Inside the taxi speeding through the air-conditioned breeze, the silver-foiled letters on the wedding invitation in my hand shimmered exceptionally bright. The name of the person who was the center of my universe and the subject of a painful unrequited love during high school. It was a day that should be celebrated, yet I couldn't stop the sharp ache in a corner of my heart. Just as I thought the scent of the Shirahama sea from those days was brushing against the tip of my nose, the world flipped violently with a ear-splitting sound of a horn.

Thud. All senses went black.

Rei | "……おい、しっかりしろよ。こんなところで寝てたら口が曲がるぞ。" (……Hey, wake up. You'll catch a cold sleeping in a place like this.)

I opened my eyes to a voice that felt both familiar and distant. It wasn't the smooth asphalt ground, nor the inside of a crumpled taxi. Beyond the slightly fogged glass window, the blue sea of Shirahama stretched out endlessly. This place, filled with the musty smell of chalk dust and the sound of cicadas, was a classroom at Shirahama High School.

I hurriedly lifted my body from where I had been slumped over the desk. The date displayed on the smartphone screen was July 2016. I had been rewound exactly 10 years back to my first year of high school, just before summer vacation.

Was it all just a vivid dream? But the sea breeze blowing against my sweat-drenched back and the sound of waves hitting my ears were far too real. Inside the classroom I faced again as my seventeen-year-old self, the friends from those dazzling days were standing there just as they were.

The one yawning lazily with buttons undone and a loose tie; the one smiling shyly while fiddling with a cap with his large frame; the one leading the atmosphere with energetic pranks; the one fixing her bangs while looking in a mirror; and the one next to her, meticulously organizing notes while nagging.