National Security operatives Huang Kai and Yan Di lead a high-stakes operation to intercept Nathan, a foreign intelligence operative carrying a metal box containing highly classified material related to China’s sixth-generation fighter program. Before Nathan can deliver the box, it unexpectedly ignites, leaving him gravely injured and destroying much of the evidence. During the pursuit, [Huang Kai] is wounded by a hidden sniper, while another officer is killed. The following day, veteran officer Zhao Hong takes command of the team. Director Wang privately informs [Zhao Hong], [Huang Kai] and Yan Di that intelligence indicates a foreign agency is attempting to recruit a high-ranking mole within their own unit, prompting a covert internal investigation codenamed Scare Out.
Unknown to his colleagues, Huang Kai becomes entangled with Bai Fan, a foreign intelligence operative who is blackmailing him with a secretly recorded video of a drunken encounter. Under duress, Huang Kai agrees to help Bai Fan remove forensic evidence from the recovered metal box. Bai Fan is also working with Li Nan, a chemistry professor responsible for leaking the classified technology, who grows increasingly desperate to flee the country before authorities identify him. Meanwhile, Zhao Hong quietly places Huang Kai, Yan Di and other team members under surveillance while withholding the full extent of the investigation from most of the bureau. To identify the suspected mole, State Security secretly replaces the recovered metal box with a decoy. Realizing the switch, Huang Kai understands that he has become one of the investigation’s principal suspects. Yan Di independently begins following Huang Kai and eventually searches Bai Fan’s apartment, although he has already removed anything capable of incriminating either himself or Huang Kai. Bai Fan later orders Huang Kai to kill Li Nan, but Yan Di intervenes and prevents the murder. As the investigation broadens, Zhao Hong briefly considers whether Yan Di himself may have been compromised after learning of Bai Fan’s connection to his late ex-girlfriend.
Laboratory analysis confirms that the stolen material is part of the stealth technology used in China’s latest sixth-generation fighter project, making Li Nan the primary source of the leak. Zhao Hong leads a citywide manhunt as Li Nan attempts to escape with Bai Fan’s assistance. Before he can be taken into custody, however, Bai Fan kills Li Nan to eliminate a potential witness. Yan Di pursues Bai Fan but is delayed when he is attacked by a foreign assassin, whom he ultimately kills after a violent confrontation. Yan Di catches up with Huang Kai as the operation closes in on Bai Fan. Huang Kai kills Bai Fan but, overwhelmed by guilt over his involvement with the foreign intelligence network and the consequences of his actions, takes his own life. Afterwards, it is revealed that Yan Di’s apparent contacts with the foreign organization were part of a long-running counterintelligence operation. Although believed by the foreign agency to have defected, Yan Di has secretly maintained a one-way line of communication with the director throughout the investigation. With his cover intact and the foreign organization convinced of his loyalty, Yan Di prepares to continue infiltrating the network and counter future activities by the organization.
