In North Korea, Eom Chul-Woo is assigned by chief director Ri Tae-han of the Reconnaissance General Bureau to assassinate Supreme Guard Command chief Park Byung-jin and the minister of state security to prevent a coup d'état. Eom kills the minister in a car accident. In South Korea, senior presidential secretary Kwak Chul-woo congratulates Kim Kyung-young for winning the presidential election. He is later informed by Li, an ethnic Korean in charge of the Korean branch of China's state security, of the assassination and the possibility of a coup in the North.

Bidding farewell to his wife and daughter, Eom proceeds to the Kaesong Industrial Region, where Park is due to arrive with the supreme leader^[a] for a North Korean—Chinese event. Meanwhile, North Korean infiltrators disguised as ROK Army soldiers hijack a US Army MLRS vehicle and launch two missiles at Kaesong. Eom tries to inform Ri about Park's absence just as the missile lands.

Surviving the attack, Eom witnesses KPA soldiers massacring the remaining survivors. Eom and two schoolgirls rescue the gravely injured supreme leader in a toy company van and escape across the border to the South with the rest of the Chinese delegation. Kwak, meanwhile, meets with CIA station chief Joanne Martin, who absolves US responsibility for the incident.

In Ilsan, Eom has an obstetrician to tend the supreme leader, but she is unable to extract a bullet lodged near the supreme leader's brain. Meanwhile, Eom informs Ri of his location, who sends reinforcements to kill the supreme leader. Ri reveals himself to be the mastermind of the coup. Eom eliminates them and evacuates him to a plastic surgery clinic staffed by Kwak's ex-wife, Su-Hyeong. Notified of the fight, Kwak makes his way to his ex-wife's clinic and is tied up by Eom along with the South Koreans. However, South Korean special forces soon detain Eom, while the supreme leader is sent to be treated in a military hospital. Meanwhile, President Lee declares martial law in the country as North Korea declares war on the South.

The next morning, Eom and Kwak shadow the director of South Korea's National Intelligence Service as he meets with North Korean military leaders at Nodongdangsa. North Korean snipers attack the meeting and a car chase ensues. Not expecting Park to be leading the North Korean delegation, Eom shoots him as ordered earlier. Meanwhile, Ri reveals his plans to attack the South by using nuclear missiles but is unable to use them without the nuclear codes. Eom and Kwak foil another assassination attempt on the supreme leader. Tensions rise as the US Air Force launches nuclear missiles at North Korea, which responds by launching a nuclear missile toward Japan. The interception by a Japanese ship causes an electromagnetic pulse which takes down the US missiles. Alarmed by the escalation, Eom convinces Kwak to leak false news that the supreme leader is dead, which leads to the North halting its plans.

Eom forms a plan with Kwak and returns to the North via a secret tunnel to confront Ri in his underground bunker. The ROK Air Force receives Eom's signal to launch missiles at his location, destroying the bunker and killing everyone. With the coup attempt foiled, newly-inaugurated President Kim announces peace and reunification talks with North Korea. South Korean officials repatriate the supreme leader in return for half of North Korea's nuclear arsenal.

A sequel Steel Rain 2: Summit was released on 29 July 2020. Jung Woo-sung and Kwak Do-won returned to star, but in different roles compared to the first film.^[14][15]

• Mutual assured destruction
• 2017–18 North Korea crisis

• Steel Rain at HanCinema
• Steel Rain at IMDb