There's a boy who is afraid of his past and there's a girl who come into his life and changed him . 

" You've changed me inside . You are right , I have changed . I tell you how I feel now rather than letting you walk all over me . Thanks for making me stronger , so I can now stand up to you . " 

She gives him strength . She encouraged him a lot . She tried her best to change him . She likes him eventhough she knows he didn't even have feelings for her . 

" Jongin ah . I mean .. K-Kai . You know what ? It's never too late to start over . If you weren't happy about yesterday , try something different today . D-Dont stay stuck okay ? Do better . " 

They are married by the decision of their parents . They are being paired together , they are a perfect match but yet they looks like strangers . 

" Yeah you're right . It's time for me to stop being afraid . It's time for me to let go of the past . What happened , happened . It doesn't matter how many times I go over it in my head , think about I should have done . It's too late . It's not going to change anything . I can't change the past . "

Until one day he get to know her secret that she's been hiding from him . A secret that related to both of them . And who knows that the cold hearted boy actually loves her as much as she loves him too . 

" One word can change your life forever . I hate you but at the same time I do falling in love with you . It's crazy how I can't stop myself from loving only you . Think about it , Kim Haru . "