Policewoman Yao Ziru (played by Wang Minyi) is particularly sensitive to the sounds, lights and shadows around her, and even the emotions of others. She uses this talent to solve the mystery of the murder. Ru is "cold" in private and rarely builds close relationships with others. In the eyes of others, she is a "bystander" in the city. Wang Mixi (played by Zhou Baihao), the manager of "Rabbit Hole", hopes that every diner can temporarily put aside the pressure of life, relax and enjoy "little happiness". Xi always has a smile on his face. He likes to listen to the stories of customers, but never shares his own stories. Ru often puts emotions and feelings into the investigation. Whenever Ru chats with Xi, the unresolved emotions are relieved, and over time the two become more and more compatible. At this time, two murders occurred. The victims were "bystanders" who indirectly caused the deaths of their relatives. Ru believes that the murderer is the same person and is determined to arrest the serial killer. However, the deeper the investigation goes, the more Ru can feel the murderer's heart, and even becomes closer to "him", which puts her in a dilemma... Can Ru suppress her inner emotions and arrest the real murderer herself?