While Seung-hee waited at a lighthouse for Hyun-jun, he was driving up to meet her and propose. However, during the drive, Hyun-jun was shot in the head by a sniper. He dies while looking at Seung-hee at a distance away at the lighthouse, unbeknownst to her. "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. 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 (Juni) and Hwang Tae-sung (Na Yoon), 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.