One night, Gui Xiaojin, a young woman living alone, is terrified when Zhang Wei breaks into her apartment disguised as a food delivery driver. She narrowly escapes danger by calling the police. As the investigation unfolds, the police discover that the terrifying intrusion was no coincidence, but an act of revenge stemming from a controversy over a postgraduate recommendation slot years ago. Li Jing died consumed by resentment, while her stepsister, Lin Yao, became consumed by hatred and secretly orchestrated an elaborate scheme. By impersonating Gui Xiaojin and stealing her identity, Lin Yao intended to take her place. When Gui Xiaojin publicly confronts the shameful truth of her past, Lin Yao's obsession finally crumbles, and she is arrested. Yet even after the turmoil subsides, a new presence begins watching from the shadows. The threat is still lurking in the dark.