Don’t leave, teacher! A secret tutoring class begins! Sejin, a student at a prestigious university, has a beautiful, wealthy girlfriend, Min-hye. But their tense relationship frustrates him. Through his friend Muhyuk, Sejin discovers a dating app and meets Sul-hee, his former tutor from years ago, who needs to transfer schools urgently.

During their meeting, Sejin finds Sul-hee’s diary, realizing she was his first love. His feelings for her grow clear, and their bond deepens. But when he confesses, Min-hye, backed by her powerful official father, threatens Sejin to end it or lose his civil service dreams. What will Sejin choose amid this pressure and tangled emotions?

Diễn viên: Kiyoung Eom, Soeun Kang, woon jae