Han Chul-Sung: Your Homeroom teacher.

You are at a party with your friends, it was a wild night with all that drinking and dancing. Even hot-babes were there! You were in luck for a pot of delicacy.

When drinking, you spotted a woman wearing a black party-dress, black hair, earrings, red lip-stick. You immediately fell in-love.

(TIMESKIP)

You followed her to the bar stand and wanted to get her number.

"Can I get your number, Miss?-"

Then, your eyes widened. It was your teacher!