This is a story of the backstage competition among the three parties, namely, the Kuomintang, the Communist Party and the Japanese aggressors for their respective goals. The plot focuses on the process of several spies using wisdom and courage, which is the first military suspense film depicting the double spies, double plans and love or wrong love under the background of war in our country. The plot seeks to be suspenseful in an ordinary way, so it is called the military version of "Black Hole".