Kim Ji Hae is 18 years old who scared to fall in love again when she got cheated by her first boyfriend with her own best bestfriend. She is very pretty with big and round eyes, emotional, un-predictable and hyper person as well. 

   She lives by herself in a very big mansion belongs to her late parents who die in an accident 5 years ago. But she have an auntie who is 30 y/o who love to travel.

One day, her aunt told her that 12 boys will move in into her mansion. Ji Hae does not agree until her aunt told her that she have a debt with them. All of them are an orphan and grew up together. They also an art student at Seoul University and Ji Hae      senior. They are were very famous at their university because they are PERFECT. But only Ji Hae knows the true about them later.

What will happen when all of them have a crush on her. But only 3 really love her since the day they met her. Will them be able to cure Ji Hae coz she is so scared to get hurts again. In the end, who will she picks?