Met You By Chance S01E03 - The Secret You Have

Yoon Young was able to enter school thanks to Hae Jun's help. As soon as she began her classes, she realized that one of her classmates was the future Ko Mi Sook. However, she was unaware of the danger that Ko Mi Sook posed, as she was extremely clever. Hae Jun ensured that Yoon Young remained at school until he could pick her up, but when he returned, Yoon Young was nowhere to be found.