Ep 1. Jung-ho and So-yeon, a cohabiting couple in their 40s, previously agreed not to have children. However, Jung-ho demands a child, using his mother as an excuse. So-yeon, an unknown actress, feels deeply betrayed, and in that moment, her body turns transparent before his eyes. Ep 2. Pursued by a mysterious floating knife, In-cheol lives with his son, Jin-woo, following a business failure and divorce. Jin-woo abandons his dreams and breaks up with his girlfriend. After they argue and blame each other, Jin-woo leaves home. The knife chasing In-cheol finally locates their house. Ep 3. A year later, Jung-ho struggles with his failing restaurant afloat, while Jin-woo wanders without a home. Jin-woo earns, borrows, and even extracts money from Jung-ho. As they clash, Jung-ho finds it increasingly impossible to understand who Jin-woo truly is.

在《冬日狂热》后，延浩和裕俊已经甜蜜相伴到第二年。穿越了最初寒冷的冬天，他们一同走过四季，终于迎来了并肩度过的第五个季节。在这个炎热而充满活力的夏天，拥有相同温度与心意的两人将面临全新的生活节点，共同开启一段关于陪伴、成长的炽热罗曼史。