Shen Zheng, a doctor in Mei City, is reborn with vivid memories of his previous life. In his past life, four university students brought back an unknown pathogen. Because he couldn't bring himself to act ruthlessly, he delayed the lockdown, eventually becoming infected and dying. This time, he immediately sounds the epidemic prevention alarm and places all four students in isolation. However, during the investigation, he discovers an unidentified animal carcass in student Chen Hao's backpack. Surveillance footage soon reveals the truth: the four students trespassed into an African epidemic zone to attract online traffic and illegally brought the carcass back to Mei City. But just when everyone thinks the crisis is over, ride-hailing driver Zhao Yong suddenly develops a high fever.