Again, Again!

A university professor, Ji-on, whose motto in life is not to stop those who come and not to hold onto those who leave. He accidentally spent a night with his student. During the first class, Ji-on's voice, which was calling out unfamiliar names in order, stopped. The murmuring sound reached the front of the podium, and Ji-on, startled, opened his lips. "...Go Yi-hyun." It was as if he had uttered words he couldn't bear to say, his darkened eyes moved towards the students. "Yes." Regrettably, Yi-hyun seemed to recognize Ji-on. "Professor. Don't you remember me?" "Have we ever met? I don't know what you're talking about. You must have mistaken me for someone else. Then, goodbye." Ji-o...