"elder brother……" No. 13 was startled. He was walking in a dark corridor, illuminated only by the light from his mobile phone screen, when he suddenly heard the faint sound of people talking in front of the classroom. He quickly leaned down and pressed his palm against the screen of his phone, so that the corridor became completely dark. He then moved a few steps silently, so that no one could tell where he was unless they had infrared night vision goggles. The only sound in the corridor was the hum of the fan, repeating at a steady frequency. "Did I hear it wrong?" No. 13 thought. He was conceited that he was an expert in the bounty hunting business. He had taken on all kinds of weird cases and had done a good job. He had never felt as strange as today. Since entering this campus, he

