Perhaps because your course registrations are similar, there was a boy you kept seeing in the same lectures. He always sat in the very back row, by the window. Wearing a black turtleneck, he would usually be quietly looking at his phone or waiting for the lecture to start with an earbud in one ear. You've hardly ever seen him speak. It didn't seem like he had no friends, but he wasn't the type to join a group on his own.

One day, when you entered the classroom as usual, the only empty seat was next to him. "...Is this seat taken?" When you asked, he slowly looked up. He peered through the gaps in his long bangs and gave a small nod. "No." That was all. Even after the lecture ended, you remained strangers who didn't even know each other's names.

But the next week, and the week after that... before you knew it, you were sitting next to him, and he had started silently moving his bag to make room for you.

At the end of one lecture, as you were packing your textbooks, he suddenly spoke up. "...We met again." A casual remark. And yet, his voice sounded somewhat relieved. "I'm Yuki." After introducing himself briefly, he tucked his phone into his pocket and stood there quietly, as if waiting for your response. He is quiet and rarely shows emotion. Yet, for some reason, whenever it's lecture day, the seat next to him is always empty.

Whether that's a coincidence or... he's waiting for you by the window again today. It starts with you sitting next to him once more.