Han Do Kyung, specially scouted by the Incheon Airport Director, willingly accepted 1/3 of the pay she was receiving when working in Singapore to come back to Korea as the chief of operations of Incheon Airport. She speaks five different languages. However, Do Kyung lives with an uneven wound of her family and a regret of leaving her sister behind. She met Kim Ji Sung, a National Intelligence Service agent and gets entangle with him. Kim Ji Sung is very passionate about his work to the extend that he is willing to bend the rules to ensure the security of the country even if he is only acting on his instincts. After being stationed at the airport, he finds himself in an emotional turmoil with a woman he used to love who is also working in the airport. At the same time, he is falling for Han Do Kyung. Kang Ha Joon, a childhood friend of Han Do Kyung is also falling for Do Kyung. Kang Ha Joon is a quick tempered with a habit of talking aggresively due to his nature of work watching over thousands of surveilance cameras in the airport but has good relations with all the airport employees even the cleaners because of his kind personality outside of work. As his friendship develops with Do Kyung, he becomes a strong source of refuge for her. But as his feelings for her grows, his relationship gets more and more complicated with a woman who is his friend, superior at workplace and unrequited love.

Han Do-kyung (Choi Ji-woo) was especially scouted by the Incheon Airport director and willingly accepted one-third of the pay she was receiving in Singapore, to come back to Korea as the chief of operations of Incheon International Airport. She is level-headed, speaks five different languages, and remains cool and calm under all circumstances. However, Do-kyung lives with the emotional wounds caused by her estrangement from her sister Yi-kyung, a pilot (Lee Da-hee).

Do-kyung's unflappability is put to the test when she meets rash National Intelligence Service agent Kim Ji-sung (Lee Jung-jae). Acting on instinct whenever he thinks national security is at stake, he often breaks rules and ruffles feathers on the job, bringing him into constant contact, and sometimes conflict, with Do-kyung. After being stationed at the airport, he encounters doctor Seo Myung-woo (Moon Jung-hee), his ex-girlfriend who is now working at the airport clinic, with whom he parted on painful terms.

Meanwhile, another airport employee is Do-kyung's childhood friend Kang Ha-joon (Lee Jin-wook). Ha-joon is quick-tempered with a habit of talking aggressively due to the nature of his job with airport security, watching over thousands of surveillance cameras. But he has a good relationship with all the airport employees, even the cleaners, because of his kind personality. As he and Do-kyung renew their friendship, he becomes a strong source of support for her. His feelings for her quickly turn romantic, despite the complication of Do-kyung being his superior at work.

But Ha-joon's affections remain unrequited, because Ji-sung and Do-kyung, despite struggling with memories and misgivings from the past, find themselves falling for each other.