In 1944, an undercurrent surged in Harbin under the rule of the puppet Manchukuo. Song Zhuowen, an intelligence agent of the Communist Party of China, used his identity as his twin brother to sneak into the Secret Service Section to gain trust. In the dangerous situation, he battled wits with various forces, collected intelligence, resolved the crisis, and joined hands with his comrades to stick to their beliefs and clear the way for the victory of the Anti-Japanese War.
