"I am getting older and older because I have a mother who acts like a child." thinks Min-ah, an ordinary high school student. Min-ah lives with her mother who occasionally acts like a child. Min-ah is a shy girl who does not have a lot of friends. That is why she doesn't enjoy school very much.
The only thing that is fun for her is to watch is Ki-soo, the boy who works in front of her school controlling traffic. He's a little crazy. Min-ah lives with the hope that someday she will also meet the fateful love of her life, just like the love that Ki-soo once had with an older student from her school. "My gosh, could there be another character that is even more eccentric!"
One day, a new family moves into the villa one floor below where Min-ah is living with her mother. It's Young-jae's family. He's a college student. The meeting of Min-ah and Young-jae is tense from the beginning. Young-jae tries to be overly friendly because they are new neighbors. Min-ah's mother prematurely assumes that Min-ah has a new boyfriend who is Young-jae. He simply goes along with her, until one day, Min-ah falls for one of Young-jae's pranks, wondering "Should I date him, or not?"