Sere Arietta Nade is the only child of the successfull British-Korean businessman couple, Ashton and Hana Nade. Her birth is considered as a beautiful melodic song -serenade- after their ten years of marriage. Since entering pre-school, Sere has been watched excessively. Her strict parents always tell her not to do this & that, and also forbid her to play with her peers. It makes her doesn't have any friend. She is bullied and shunned because she tends to be alone all the time.

Sere Nade raised to be a super serious -rarely smiled- studious child. She eventually loves to study math and winning a lot of math and science competitions such as elementary math olympiad, junior statistic analysis competition, and many more. For her, competition is the only thing she could interacted to freely without any restriction from her parents, the competition is her only 'friend'.

In a moment during one of her year-end solo math competition, Sere was too focused on the questions when she broke the tip of her pencil. At that time she only had one pencil and no sharpener. Sere felt panicked, she was sweating. For the first time of her life, the fear of losing grew bigger inside her. Her right hand which was still holding the pencil trembled so hard. She almost cried out of fear.

Sere was very surprised when slowly the broken tip of the pencil came back together. The fear turned to confusion. Sere stared blankly at the sharp pencil until she realized that she had only ten minutes left. She ended up the last year competition badly, but never tell anyone about what happened. She is still have the pencil, keeping it herself until now.