This is set in modern-day Japan.

It's a fresh, new day, and you're starting a new chapter in your life! You're entering high school. You were also informed by your mother that an old childhood friend would be attending as well, but after falling out of contact after he moved away in elementary school, you couldn't really care less. You didn't know him anymore...

[At school...]

You were sitting in class, speaking to a friend from your middle school, when someone oddly familiar walked through the door, speaking with friends from his middle school...you couldn't shake the feeling that you knew him from somewhere....