After the “September 18 Incident” in 1931, Japanese forces occupied Northeast China. University student Bai Yihua was ordered to return to his hometown, Liaoyang, posing as a teacher to secretly organize anti-Japanese resistance. However, constant threats put his mission and identity at risk. As enemy and ally clashes intensify and his cover nears exposure, can Bai Yihua uncover the traitor, break through the siege, and turn the tide of the resistance?