Gain is a person who thinks that she is always right. She don't care if she hurt a lot of person, what important to her is do what she wants. Then, one day, her world turned upside down. Because of her bad attitudes ,her parents decided to separate her from them to know what she have done. To learn her lesson. But what happened is the complete opposite of what they thought. She turned away from them and rebelled. She used her money and rented a big apartment but as months goes by, she's loosing her money so there's no other choice but to have another that will rent the apartment so that her expenses will be reduced. And here, she will meet Jo Kwon, who is kind, innocent and pure as an angel! What will happen now if a devil and an angel are together in one roof?!!!!!!!