What if, a member of the nation girl group which is Girls Generation has fallen in love with her group mate? She is a visual of the group and she's falling in love with the 2nd oldest of the group. She has harbored her feelings since before they are debut. At first, she regard it as a love between a dongsaeng and her unnie. And as times goes by, her feeling has grown up as a lover. But what if, her unnie whom has been fallen in love by her just regard her as her dongsaeng? Even She has a boyfriend. It's like one sided love. 

Her broken heart, makes her truly depressed. She never fallen in love with someone. And when she expressed her feeling to her crush she got rejected, even in front of her other unnies and her dongsaeng. But what if her depressed didn't only makes cried all her night whenever thought about memories of both of them? Likes she said the words inadvertent that never thought by her but it can make her life is totally changes? Changes into something that never expected by herself and the other and induce her group in bad situation.

will her crush realize how was the feeling for her all this time after her life was changed? 

or maybe the other her group mate who has feeling for her take this chance?