Moonbyul is a 16-year-old High School student, who has straight A's and gets bullied by the most popular girls in school. 

She is the middle child, having an older twin brother and a younger sister.Her parents divorced, having her father leave to the U.S along with her brother. 

She is an introvert and the only person besides her family that she talks to is her best friend since elementary Ahn Hyejin also known as Hwasa. 

She lived her life in a routine. During the week when she goes to school she would:

1. Exercise early moring 

2. When she returns would take a shower and get dressed for school.

3. Eat breakfast

4. Then head to school.

5. School

6. Afterschool she would study 

7. Head home and have dinner 

8. Read before going to sleep

On the weekends she would have the same routine, but instead of school all she would do is either read or play video games. Unless she is forced to go out by her best friend Hwasa.

Her life becomes a mess when someone returned.