During the most difficult period of the Anti-Japanese War from 1937 to 1945, Qin Chuan, an underground intelligence worker of our party, successfully broke into the Mei Agency, a Japanese spy agency in Shanghai, under the secret planning of the organization. Prior to this, Qin Chuan had been lurking in the Kuomintang Fuxing Society for a long time, successfully obtained intelligence, and eradicated the Kuomintang spies hidden in our party organization. The news that Qin Chuan "surrendered" to the Mei Agency received close attention from the Kuomintang Military Intelligence Bureau, the Japanese, and our party's underground organizations. In order to smoothly implement the lurking plan and obtain confidential intelligence from the Japanese army, Qin Chuan relied on wisdom and extraordinary courage to move forward step by step, turn danger into safety, seize the opportunity to strike the enemy, and defend the organization. Xia Lan, who was also an intelligence worker of our party, was Qin Chuan's lover. She used her identity as a nurse to cover Qin Chuan. They knew each other but could not stay together. The heart-wrenching emotions turned into a passion for serving the country. At the same time, patriotic detective Shen Ruohan and military female spy Ye Linlin were involved. In the emotional entanglement, they sacrificed their lives for the sake of national justice. In the end, Qin Chuan and Xia Lan successfully completed the tasks assigned by the Party, but Xia Lan died heroically for the revolutionary cause.