Danielle and Heeseung have been best friends since the day they were born. Danielle is very kind-hearted, ambitious and smart. Heeseung is charming, lovely and mischievous. They've been spending every day together. Experiencing middle school and high school drama, which brought not only pleasing things to their relationship but also hardships they learn to overcome. They can't imagine a day without each other until they part ways by getting to different universities.