In Jinhai, China, a spy game has shot up in popularity among young people. As it turns out, the game was developed by an overseas intelligence organization known as "Night Fog." They are using players to engage in espionage activities without their knowledge and also seizing the opportunity to cultivate spies among them. The evil seeds of the game have been spreading silently throughout the city. At this time, Gao Tian Yang, the head of reconnaissance at Jinhai National Security Bureau, works together with intelligence officer Wu Xi to dive deep into the game as they investigate a case surrounding laboratory secrets that have leaked. During their investigation, the two rescue Huang Zi Cheng from a conspiracy, who is like a little brother to Gao Tian Yang, and in turn, he becomes their informant thanks to his rich experience in the spy game.