On the surface, he is Lin Feng, a mathematics teacher at Fengtang International High School, but in fact he is a former special forces elite codenamed "Feng Yun". When his former comrade "Yu Drop" was brutally murdered and a USB flash drive containing top-secret information was handed into his hands, the peaceful campus life was suddenly torn apart. On one side are the youthful laughter of the students and the warm eyes of colleague Liu Shishi, on the other are the suspicions of traitors within the organization and the deadly threats from hidden enemies. Lin Feng must walk carefully between his dual identities, track the bloody truth amidst the sound of reading, and protect his unfinished mission.
