Byun Baekhyun. A famous model in Korea. His good looks make all women addict obsessed with him. His name often appears in newspapers or magazines. He is also well known in the social networking site. He is often chosen as the 'Ideal Boyfriend/Husband' by female artists. He comes from a wealthy family. His father, Mr. Byun, was one of the well-known corporate in Korea. While his mother, Mrs. Byun, was a surgeon at the general hospital in Seoul.

But, it was lost when he met a naughty girl. He thought that she is the only one who does not recognize him. Kim Hyuna. A naughty girl, cheerful, and a little childish. She lived with her sister and their way of life is simple. Their parents died when she was 11 years old. People always ask her to be an artist because of her beauty. But, she will not. Unlike Baekhyun, Hyuna doesn't like her life being controlled. That's why she did not want to be an artist because artists are always controlled by their company.

One day, something happened unexpectedly. Baekhyun and Hyuna had to married. Otherwise, Baekhyun popularity will decline. With the nobles, they were married. Their life is not as beautiful as newlyweds. They chose to make a contract that only the two of them knows. They have agreed not to tell anyone about the contract. When the contract was signed, they were satisfied.

They fight like a kid every day. 'Pikachu/Wolf'. That is the nickname used by Baekhyun for Hyuna. While 'Chicken/Monkey' is the nickname given to Baekhyun by Hyuna. They hate each others. Hyuna always complain about Baekhyun on her boyfriend, while Baekhyun also complaining Hyuna on his girlfriend. The more they fight, the more they become close.

When they have just to be nice, a third person comes in the way. Baekhyun's girlfriend. Hyuna's boyfriend. What will happen to them? Will they still continue with the deal set to expire at a specified time? Or they will break up before the date?

'If not forever, please stay with me as long as you can.'