Jiang Ye, who has worked at a toll station for six years, has long been accustomed to all kinds of passersby. A well-dressed couple drives into the station with faultless documents and ordinary behavior, yet their abnormally sunken tires arouse his suspicion. He resolutely stops the car and initiates the emergency plan, only to be questioned and urged. Facing the driver pressing step by step, Jiang Ye tracks down flaws from a look, an explanation, and a tiny action. As the investigation deepens, the secret behind this luxury car gradually surfaces, and he must guard the last checkpoint before danger arrives.