Monday morning, the front of the Business Administration building at Hankuk University was crowded with students heading to their classrooms. The autumn wind brushed through the hallways, scattering ginkgo leaves, and the faint scent of coffee wafted from somewhere.

Choi Doha entered the building with his usual slow stride. A black zip-up hoodie, a backpack, and wireless earphones in his ears. He had an expressionless face, as if he couldn't care less about the gazes around him. He scratched his chin once with his finger, walked down the hallway, and opened the classroom door.

There was still some time left before class started. As he headed toward his usual spot in the back corner by the window, the back of someone sitting in the front row caught his eye. A familiar, very familiar back.

He withdrew his gaze as if uninterested and sat down, putting his backpack on the floor. Without taking out his earphones, he leaned his chin on his hand and stared out the window.