Yu Xiaoxuan, a student of modern history, was attracted by an antique pocket watch when she visited an exhibition of cultural relics of the Republic of China. After touching it, she suddenly traveled to Shanghai in 1935 and found herself in a completely unfamiliar era.
Xiaoxuan was almost knocked down by a rickshaw in the chaotic streets of Shanghai, but was rescued by a passing young officer Cheng Yuanzhi. Cheng Yuanzhi was full of suspicion but was unconsciously attracted to this woman who dressed strangely and behaved inappropriately.
Xiaoxuan was taken to the police station for interrogation. She fabricated her identity as an overseas Chinese who had returned from overseas, but could not explain the lack of many basic common sense. Cheng Yuanzhi bailed her out with hesitation.
Since Xiaoxuan had nowhere to go, Cheng Yuanzhi reluctantly agreed to let her stay in his home temporarily, and the two began a wonderful cohabitation life. Xiaoxuan is full of curiosity about Shanghai in this era, while Cheng Yuanzhi becomes more and more fascinated by this mysterious woman.
In the process of getting along, Xiaoxuan inadvertently revealed her knowledge of future historical events, which aroused Cheng Yuanzhi's vigilance. At the same time, subtle emotions began to arise between the two, and Xiaoxuan found that she had feelings for this upright officer that transcended time and space.
Xu Manli, the daughter of Cheng Yuan's boss, was hostile to Xiaoxuan and secretly investigated her identity. At the same time, Xiaoxuan discovers that Cheng Yuanzhi is about to be involved in a dangerous mission, and historical records indicate that he may die as a result.
