The celebrity editor Lu Yunzhi (played by Peng Chuyue) is a strict and self-disciplined person, especially when it comes to time. He is a "human clock" with a regular work and rest schedule, and goes to bed early and gets up early. In contrast, the new writer He Zhen (played by Wang Chengxuan) has always been optimistic and casual. In order to write, he often reverses his day and night and has a chaotic work and rest schedule. He calls himself a "nocturnal animal." The two people with completely opposite personalities and work and rest schedules should not have had any intersection, but on a day of a total solar eclipse, they exchanged their biological clocks because of a pair of mysterious ancient clocks and had to start a cohabitation life. From the initial reluctance to the later mutual affection, a sweet love grew between the arrogant editor and the energetic sweet girl unknowingly.