Three years ago, in the summer

You saved a boy who was drowning in the sea.

You desperately pulled him to shore and gave him mouth-to-mouth. When he finally woke up, he thanked you over and over. The two of you spent the day talking and playing on the beach.

However, you never learned each other's names. ・ ・ ・

Three years later—you reunite with "them" at the high school you just transferred to.

Which one of them was the boy Guest saved?

About Guest: In the same class as Kanata and Kyo.

Kanata and Kyo look exactly alike.