In his previous life, Zhou Shan, head of airport quarantine, let four adventure streamers suspected of infection leave out of compassion. The virus spread, and he was scapegoated, infected, and killed. Reborn, he decisively seals off the arrivals area, standing firm against pressure from an MCN company, influential parents, and public opinion. When location data and videos are recovered, the truth emerges: the four had trespassed into a forbidden zone abroad and secretly kept live fruit bats. A laboratory subsequently detects an unknown virus, and Zhou Shan realizes that the true source of infection may already have spiraled out of control overseas.