Forced to break up with her boyfriend Jongin and get engaged with the rich bachelor Luhan, Naeun isn't willing to accept the marriage. However, Luhan asks her to give him a chance. To give him one month to make her fall in love with him and if at the end she doesn't fall for him, they can break the engagement. Completely sure that she isn't going to fall for his charms, Naeun finally accept. But, what will happen? Will she fall in love with Luhan at the end? Or will she go back to her loving and caring boyfriend, who isn't willing to give up on her?

Characters:

Son Naeun: 20 years old

Her life was perfect until she was forced to marry someone she didn't love. Now she has one month to make a choice..

Lu Han: 24 years old

Rich and young bachelor. He had been in love with Naeun for a long time, even if she doesn't know him and he will try to win her heart.

 Kim Jongin (Kai): 20 years old

Naeun's loving boyfriend, who won't give up on her even if she is forced to marry someone else. He won't let her fall for him.

Minor characters:

Son Dongwoon - Oh Hayoung - Kim Joonmyun (Suho) - Park Chorong - Kim Minseok (Xiumin) - Hong Yookyung 

& Probably others