One spring day, Kang Hyeon climbs Bugaksan with his junior Seon Woo who was recently discharged from the military. Their conversation naturally summons their past lovers. Their relationship was as if they were mountain paths, uphill and downhill, and sometimes lost and wandered, but it was cool as the wind felt under the shade of a tree, and there were times when it was a shout from the peak as if it had the world. As they line up their love stories like a letter of apology, the two are excited about a woman who suddenly passes by them while taking steps toward the summit, tired of the nutritional advice of the uncle who descends. How high should they rise to understand their hearts and know their love?