In the 1930s, Xu Congliang, a puppet Manchukuo policeman with outstanding ability, wit and courage, but no firm belief, won the trust of Jin Ronggui, the director of the Harbin Police Department, with his outstanding ability to solve cases in the sinister internal struggle of the Harbin Police Department. On the other hand, Xu Congliang, out of his love for Guan Haidan, the head of the Criminal Section of the Police Department, and his admiration for the Communists, helped Guan Haidan out of danger again and again, and fought side by side with Guan Haidan in many operations, growing into a true Communist Party member. In the bloody puppet Manchukuo Police Department, Xu Congliang was always on the edge of a razor, and he and Guan Haidan went from hostility to cooperation, and then to heart-to-heart communication. In the end, he won Guan Haidan's love and gained a firm belief.