We are neither kids nor adults. When do we become adults then?

Min-jae and Seo-yeon are no different from ordinary 17-year-old high school students. Min-jae is silent and sensitive, yet a good student. Seo-yeon who plays the piano wished to enter an arts high school but failed. As they grow into adults, their surroundings and the reality they face get harsher. These two somehow similar but different friends get closer as they overcome their growing pains together.