Class 4 of the 2nd year of a boys' high school strives day by day under the guidance of their homeroom teacher, who considers anything that hinders university entrance exams to be uneducational. Hyun-seop, though the class president, approaches class life cynically. He rather seeks an interlocutor in his encounters with his girlfriend Ji-yeon. Ji-yeon wants to study Korean Literature instead of piano, which she has been playing since childhood. At the start of the second semester, the homeroom teacher is hospitalized for a long period, and a new teacher arrives. He appoints a new class president regardless of grades and encourages students to take interest in each other. Although they are a small number of students, they find a sense of harmony and unity at Odae Mountain. However, the chaos in the class deepens, with students giving up on the humanities track, and others whose academic performance derails due to their parents' indifference. The most shocking thing is that Ji-yeon collapses from a nervous breakdown due to conflicts over her future path. Under the warm guidance of the new homeroom teacher, who observes these conflicts, deviations, and wanderings, the students return to the class. However, they can do nothing in the face of the challenge of university entrance exams. They become third-year students, accompanied by the homeroom teacher's words as they gaze at the snow-covered schoolyard.