Iris () is a 2009 South Korean television series starring Lee Byung-hun, Kim Tae-hee, Jung Joon-ho, Kim Seung-woo, Kim So-yeon and Choi Seung-hyun. The plot revolves around two best friends from the 707th Special Mission Group recruited into a secret South Korean black ops agency known as the National Security Service. As the two friends find their loyalties tested and forge new, unlikely alliances, the journey takes them from their home country to Hungary, Japan, and China where they find themselves at the center of an international conspiracy. It aired on KBS2 from October 14 to December 17, 2009, every Wednesday and Thursday at 21:55 (KST).

With a budget in excess of , Iris along with its spin-off Athena: Goddess of War, share the record for the most expensive Korean dramas ever produced. The series was a critical and commercial success, with an average viewership of over 30% in addition to ranking as the top program consistently every week after its debut. The series also took home many of the highest honors at the 2009 KBS Drama Awards, including the Daesang Award for Lee Byung-hun.

The success of the series has led to a feature film, a 2010 spin-off, and a sequel series in 2013.

Synopsis Two best friends who are so close that they are like brothers, Kim Hyun-jun (Lee Byung-hun) and Jin Sa-woo (Jung Joon-ho), train under the Republic of Korea Army's 707th Special Mission Group until they are scouted by NSS (National Security Service). The two were independently scouted by the beautiful NSS agent, Choi Seung-hee (Kim Tae-hee). Unaware they have been scouted, the two are secretly captured and subjected to a simulated torture test. Both pass the test and are deemed qualified to become NSS agents. In the process, they both fall in love with Seung-hee, who has kept the scouting process a secret from them.

After completing the test, Hyun-jun and Sa-woo are introduced to the director of the NSS, Baek San (Kim Yeong-cheol). Baek San explains to them that the NSS is a secret organization tasked with preempting foreign threats and protecting the country's interests through wetwork operations, including assassination of anyone who could be a threat to South Korean (SK) national security. Since its founding in 1976, during the rule of Park Chung Hee, the agency's existence has remained a state secret from everyone, including the President.

After entering NSS, the pair learn that Seung-hee had been their undercover scout agent. While both were surprised and somewhat hurt, Hyun-jun is angered the most as he feels his heart was toyed with. During a team celebration dinner, Hyun-jun confronts her alone and the two embraced the passion they have for one another. Afterward, the two maintain a secret romantic relationship.

Hyun-jun is then sent off on a solo mission to Budapest, Hungary. There, Hyun-jun accomplishes his mission and while escaping, is wounded. Shortly later, Hyun-jun finds out that he was betrayed by fellow agent Sa-woo. Seung-hee attempts to help Hyun-jun escape, but a car explosion separates the two and both are misled into believing that the other is dead. Hyun-jun is then saved by an unknown voice and learns of the secret society "IRIS".

One year later, Hyun-jun returns to Korea to seek revenge. During this time, North and South Korea are set to reunify. However, the members of IRIS are intent on preventing the reunification. They attack a local mall and take hostages so that they can blackmail both sides of the Korean government and to threaten SK's president into announcing their political stand to not unite with NK. Hyun-jun becomes the negotiator for the president Cho Myung-ho (Lee Jung-gil) and for the hostages' release. Eventually, Sa-woo is killed. With the obstacles to the reunification process removed, the peace talks resume.

At the reunification summit, the president personally requests Hyun-jun to be at his side. Concurrently, NSS agents realize they have been duped: the presumed dead IRIS agents at the mall crisis were actually the hostages. The true IRIS agents escaped and infiltrated the summit to kill all delegates. IRIS agents kill and replace various security agents for a massacre. Fortunately, it fails due to Seung-hee's intervention. She pretends to be an IRIS agent and uses the confusion to stop them. This creates mass panic as IRIS agents make their stand against all security forces. Ultimately, the SK president and NK forces survive the assault and Hyun-jun saves the day again.

In the aftermath, Hyun-jun and Seung-hee leave NSS for a normal life. While Seung-hee waits at a lighthouse for Hyun-jun, he drives up to meet her and propose. However, during the drive, Hyun-jun is shot in the head by a sniper. He dies while looking at Seung-hee at a distance away at the lighthouse, unbeknownst to her.

Cast Iris featured an ensemble cast split between characters of North Korean and South Korean descent. Because the series explores the tension and mentality behind the two sides of the conflict, both the North and South perspectives are shown at length. The plot focuses on the cast overcoming the manipulation they face at an international level and occasionally attempting to reconcile their differences to fight an evil greater than either side ever acknowledged, making way for scenarios in which their allegiances are stressed and put to the test.

Main

Lee Byung-hun as Kim Hyun-jun A soldier with the South Korean Special Forces, Hyun-jun has floated through life with little attention for the details. Possessing a photographic memory, top athletic ability, and proficiency with most firearms, he has little difficulty distinguishing himself as a member of the NSS. Assuming the code name "TK1" during operations, he is frequently paired with his brother and colleague Jin Sa-woo. Kim Tae-hee as Choi Seung-hee Ranked as a "Team Leader" within the NSS, Seung-hee is an expert profiler that assisted the second-in-command, Park Sang-hyun, with recruiting Kim Hyun-jun and, more directly, Jin Sa-woo. Admired for her beauty and perspicacity, Seung-hee is universally liked within the organization and remains very close with fellow NSS member Yang Jung-in. Jung Joon-ho as Jin Sa-woo A friend that has grown up alongside Hyun-jun, Sa-woo is the more level-headed and responsible of the two. As members of the Special Forces, they often found themselves in fierce competitions, and after joining the NSS, find themselves competing for the affection of Choi Seung-hee. In accordance with Hyun-jun's code name, he becomes known as "TK2". Kim Seung-woo as Pak Chol-yong A seasoned and steadfast supporter of the WPK, Pak Chol-yong is the head of the North Korean security team responsible for escorting and protecting heads of state on diplomatic missions. He first encounters Kim Hyun-jun as they are caught in a political impasse in Hungary—one that leaves Pak and his entire team at the mercy of their superiors should they not resolve the situation quickly in their favor. Kim So-yeon as Kim Sun-hwa Despite being one of very few females to achieve her status, Kim Sun-hwa has gained the trust and acknowledgment of her colleagues in the North Korean security forces. As a subordinate of Pak Chol-yong and a ranking officer in his security outfit, she has great admiration for her superior and harbors deep resentment for the South. She falls in love with Hyun-jun, who showed her mercy. Choi Seung-hyun as Vick A mysterious assassin working for an even more mysterious organization, Vick answers to a man known only as "Mr. Black." Though of apparent Korean descent, his actual origins are unknown and he communicates fluently in both English and Korean. Often, he is responsible for eliminating political targets and retrieving, as well as destroying, sensitive information at the behest of his superiors

Supporting National Security Service (NSS) The NSS is headed by Baek San (Kim Yeong-cheol), its standing deputy director only in title and the man responsible for the recruiting of Hyun-jun and Sa-woo. The named director of the NSS comes and goes with each change of power in the presidency, but it is the deputy director that oversees the organization. Baek San's motivations for many of his actions are mysterious, occasionally outright inconsistent with that of the general national interests. Due to the very existence of the organization being kept secret, he enjoys a state of personal protection that few others do.

While Baek San oversees the organization, the acting chief director, Park Sang-hyun (Yoon Je-moon), is the general supervisor and runs the daily operations of the NSS. He fabricated the understanding but also intransigent where failures are concerned, often personally dealing with each and every agent. For field assignments, he watches over and commands all missions set domestically.

Many of the NSS agents have close personal ties to one another, and the floor supervisor and head of security resources, Yang Jung-in (Kim Hye-jin), is no exception. She is often viewed as a dependable and accommodating authority figure and remains a very close friend to colleague Choi Seung-Hee.

Being the South's first line of defense against foreign threats, the NSS houses technology unavailable to their sister intelligence agencies. The two primary tech agents, Yang Mi-jung (Hyun Jyu-ni) and Hwang Tae-sung (Kim Dae-jin), are often responsible for ensuring field agents have all that is required to see their missions through. Mi-jung does not meet the expected conventions of someone involved in national intelligence. Given that her sense of fashion and general interests are more contemporary than that of her associates, she often stands out from the others, but her status as the top hacker in Korea has made her irreplaceable. Still, Tae-sung remains the more perdurable of the two and is often instrumental in the success of a number of operations.

The forensics and scientific investigations section is headed by Oh Hyun-ku (Yoon Joo-sang), an eccentric that is the eldest of the general staff. He often exhibits a fatherly relationship with many of the agents, including Mi-jung and Seung-hee.

The Blue House Due to the overarching plot of the series involving the disputes inherent to the Korean Peninsula and the intricacies of the foreign relations between the North and South, the Blue House and its primary staff are featured prominently throughout. The candidate that wins the election and assumes office is eventual President of South Korea Cho Myung-ho (Lee Jung-gil). His administration begins with his undertaking the grand task of forwarding talks of reunification between the North and South after witnessing the grim reality that is the struggle between the two nations. With strong ambitions, he leads diplomatic outreaches with the North that no one expected of a candidate so early in his term.

President Cho's chief advisor and head of his cabinet is Jung Jyun-jun (Jung Han-yong), and is one of the few around him that the president feels he can trust with any information, no matter how sensitive it may be. Later in the series, he becomes the only reliable lifeline the president has against the influence of sabotage originating inside and outside the Blue House.

The secretary to the president, Hong Soo-jin (Myung Ji-yun), tends to find herself at odds with the chief advisor. She rarely speaks her mind freely and appears to have allegiances beyond those that are already apparent.

Others Given the wide range of countries the characters find themselves in throughout the story, a number of recurring characters arise from countries outside of Korea.