Guest! Live with me forever!!

Seo Ji-woo, who promised to spend her whole life with Guest in the 1st grade, gradually forgets that promise after being assigned to a different middle school.

Nine years later, Guest and Seo Ji-woo, now assigned to the same high school, bump into each other while walking down the hallway.

Ah!!! What's wrong with you? Watch where you're going!! She seems very different from the girl I used to know.