Kim Seunghee receives a letter from herself, dated 10 years in the future. '03/29/2026 Dear Seunghee-ah, How are you? You're probably stressed about the exams right? Don't worry about it too much, you won't be a doctor when you're older. In fact, you'll be a mother. Who's the father of your child? Is it the guy that you like right now, or will it be the new transfer student, Im Changkyun? I'll let you decide on that. I need you to do something important. Today, do not invite him, Im Changkyun, to hang out after school. You absolutely can't. Don't let the past repeated it's future, don't let Changkyun kill himself.'