Mission: Possible

The Chinese MSS passes information about illegal firearms to Korea and assigns rookie Wong Iring to infiltrate as Yoo Da-Hee. Iring travels to Korea and teams up with detective Woo Soo-Han, a former special forces officer. Da-Hee explains the mission and identifies the target, SI Chem Park Du-Sik, a China-based rare-earth importer involved in arms smuggling. They decide to tail Du-Sik to a cafe in Gangnam.

The duo follows Du-Sik to a cafe in Gangnam and begins gathering intelligence on his movements. Da-Hee coordinates with Soo-Han, presenting Du-Sik as the key arms smuggler they must expose. The tension builds as they monitor his routine and check potential signals of the operation.

During a topsy-turvy ball dance, the duo manages to acquire Du-Sik's phone, only to realize it is a flip phone. They return the phone, and Du-Sik receives a call; he is killed with a dart and his death is later staged as a heart attack. The hit is clean, leaving no obvious trail for investigators.

The next day, Soo-Han and Da-Hee receive news that Rodeo, a mob boss, has been shot while leaving his club. The incident signals escalating involvement of powerful criminal forces around Seoul. They begin connecting the dots between the arms operation and rising crime networks.

After interrogating a fortune teller, they head to the Axe Clan's rival territory and meet the clan's boss. They are attacked by masked men but manage to escape, retrieving the rival boss's phone in the process. The sequence reveals the intertwined web of rival gangs and arms networks.

With help from a hacker, they reach an address where the person is found dead; they deduce the person is Kim Yeong-Gu, Mugwang International's security head, who had been killed three days earlier. They learn about its executive Director Jeon-Hoon, and recall that Jeon-Hoon threatened Du-Sik after he checked his phone. The discovery ties the local arms operation to Mugwang's corporate machinery.

The team connects the threats to Jeon-Hoon and learns of a party at Alvin Hotel the next day. Soo-Han and Da-Hee decide to attend the party to keep close to the suspects. They prepare to confront the players behind the arms deal.

At the midnight arms deal between the Axe Clan and their buyers, Soo-Han and Da-Hee are exposed as investigators. They are captured and brought before Jeon-Hoon, who orders Soo-Han to kill cops at a local police station in exchange for Da-Hee's life.

Soo-Han is escorted to the police station but fights back, injuring Jeon-Hoon's men, and returns to the hotel to find Da-Hee being moved away. The police arrest him, and the NIS arrives to reveal Da-Hee's true identity and her role as a sacrifice in the mission.

Soo-Han escapes custody and reaches the hideout where the arms deal is proceeding. He frees Da-Hee and kills Xia-rong, one of the assassins and Da-rong's brother, triggering a full gang counterattack.

Soo-Han and Da-Hee fight through the attackers, killing or arresting all the gangsters, including Da-rong and Jeon-Hoon. The criminals are neutralized and order begins to return to the streets.

Soo-Han is arrested but offered a deal by the NIS and MSS to become a secret agent in exchange for his release. He accepts, and he and Da-Hee are sent to Russia for their next mission, continuing their covert partnership.