She used to have a normal life. She used to live alone in a regular apartment. Her life used to run smoothly. But it changed when suddenly her mom came to her apartment with her friend.

 "You will move to your new apartment soon. It's a big apartment and I'm sure you'll like it. But please...." Her mom's friend said, "Take care of my son."

She looked at her mom's friend's face with an are-you-kidding-me look. But then her mom glared at her and told her to smile. Yeah, she could do nothing. At least, she got to get a new friend. 

She didn't know that she was gonna live with Kim Myungsoo, the school's kingka. The school's prince who was always disturbing her. She hated him, and he hated her too. Both of them couldn't believe that they would live in a same apartment together. After knowing that she was gonna take care of Kim Myungsoo........

Everything changed.

That girl was in a big trouble.

That girl couldn't live happily.

That girl couldn't sleep all night.

That girl was always busy.

And do you know what?

That girl was you.