Dongwoon always celebrate his birthday every year. For his birhtday is a special day that it has had throughout life. In contrast to Hyuna who always hated birthdays. She did not like a birthday or anniversary. Dongwoon and Hyuna is classmate who has the same birthday. However, they both have a different personality.  Dongwoon looks cool and always friendly to everyone, while Hyuna tomboyish girl who hates  all that she doesnt like.

One day, in which  their birthday came, Dongwoon who always celebrated his birthday on purpose to not celebrate it for some reason. That's because he was going to celebrate with someone who has captivated his heart. Who is the one who has captivated his heart?