The exhibition hall was temporarily used as a gift exhibition for alumni donations during the centennial anniversary period. The security system underwent maintenance and renovation six months ago, including 31 monitors, electronic password locks, and infrared alarms. The city's network has been hacked, and the security system of the exhibition hall has been affected. Engineers from AAA Network Security Company have been invited to repair it. After the repair, the security team leader personally closed and locked the entrance of the exhibition hall. The next day, it was discovered that the KB503 meteorite exhibit had been stolen, but monitoring and alarm systems did not detect any abnormalities. Detective Mai Jie suspected that the security system was tampered with and investigated AAA company engineers, but police technicians confirmed that the system was functioning properly. Technician Cui Zheng raised the possibility of security guards stealing, and Mai Jie decided to re investigate the scene to find clues.