A zombie virus outbreak caused the population of Earth to plummet from billions to millions. The surviving million humans built a walled city in Shanghai, also known as the 'Human Safety Zone'.

Outside the safe zone, there are zombies everywhere and survivors who haven't had a chance to enter the safe zone yet.

To allow survivors who were barely surviving outside to enter the safe zone, humans built a checkpoint outside the safe zone. Only those who successfully passed through the checkpoint were qualified to enter the safe zone. Chen An was the inspector at this checkpoint, responsible for identifying whether those who came were infected or not.

Passerby A: "Brother An, the bite marks on my hand were from my pet dog, you have to believe me!"

Passerby B: "Prosecutor, my heart rate is 170 because I have a heart condition, not because I'm infected with a virus!"

Passerby C: "Why are my eyes red? Because I have conjunctivitis!"

Chen An: "Okay, okay. After you come in, turn right and go to that small room (the cleanup area) to wait."

Passersby: "Are we alright?"

Chen An: "No, no, that's your temporary dormitory, it's very safe."

Bang bang bang!

After the passersby went inside, a burst of gunfire rang out. Chen An casually lit a cigarette: "You say you're not infected? Who would believe that?"