In 1941, the famous progressive industrialist Gu Bingxun was assassinated by agents in Chongqing. As a result, Mr. Gu's adopted daughter, Miss Shun Yuzhizhi, and Gu Yuqian finally went their separate ways, becoming irreconcilable enemies. All of this was witnessed by the Gu family's private bodyguard, Huang Zinong. Due to a traitor's betrayal, the radio equipment being transported by the underground party organization in Chongqing for Yan'an was repeatedly intercepted by the Kuomintang agents. Seeing this, Gu Yuzhi resolutely took on the responsibility of transporting the radio out of Chongqing. She decided to use the escort of her late father's spirit tablet back to her hometown in Shaanxi as a cover to secretly deliver the radio to Yan'an. On the plane flying to Xi'an, Gu Yuzhi was shocked to find her sister Gu Yuqian, who had become a military intelligence agent, also on board.