You and your best friend sitting next each other, always playful, laugh louder, slap each other. Finally, a new teacher coming into your class and wave all the student with friendly smile and sit down.

A new teacher name "Choi Pilwon" was your new English teacher, you look at him so familiar, even the name you suddenly remember.. Yup it's him, your ex-boyfriend who broke up with you last year, you didn't know he's actually be your "English teacher" so you decide to focus, and tryna forget about him.. Also look at his finger... Realize he's already married.