Due to her anger management issues while working at her previous team, Transportation Services, Han Yeo Reum is transferred to Passenger Services. However, she is late on her first day at work. When she comes in, she hears a coworker asking his superior why they should take in someone so troublesome.

After finding out that Soo Yeon has only been working at the airport for 4 months while she has worked for a year, Yeo Reum becomes enraged. She goes to Team Manager Yang Seo Goon and asks her how she could appoint him as her mentor. However, Seo Goon tells her that if it hurts her pride, she should do well at work because that is the only thing that matters.

Yeo Reum finally realizes that Soo Yeon had saved her from a flying car on the day of her job interview. However, Soo Yeon tells her that he does not recognize her and that they have never met before. Despite all this, she thanks him for saving her life. Meanwhile, someone puts in a call to the airport, claiming that they have installed a bomb.

Yeo Reum and Soo Yeon get into an argument. She tells him that unlike him, many people including herself need to work their hardest in order for their superiors to recognize them. However, he tells her that she simply has a victim mentality and lacks self-awareness.

Soo Yeon tells Yeo Reum that he cannot feel pain in his right arm. After hearing this, Yeo Reum begins to become more and more curious about him and the story behind his painless arm. Meanwhile, Seo Goon’s team moves from Terminal 1 to Terminal 2.

Words spread regarding a dispute between a passenger and Yeo Reum and a Security Team employee. Because the passenger got a scratch on her face, she has declared that she will sue the airport. No matter how much Yeo Reum tells the others that it was not their fault and that the passenger had attacked them first, she has a difficult time convincing them.

Due to a horrible car accident years ago, Soo Yeon was at the brink of death and barely survived. As a result, he was given a machine-like right arm. Ever since, he refused to allow anything to move his heart. However, after meeting Yeo Reum, he decides to work at the airport for a bit longer and also becomes interested in her.

Ian Santos, a Filipino, is caught trying to enter Korea with a forged passport. He begs the Immigration Office to just allow him to be with his wife while she gives birth and promises to leave the country right after. However, he is forced to go back to the Philippines right away. While on his way to the plane, he pushes an accompanying staff worker and runs.

A plane tries to land at Incheon airport. However, as the plane descends near the airport, fire erupts from its engine, and the entire airport falls into chaos. Soo Yeon finds Yeo Reum being extremely nervous and finds out that her mother is on that plane. After thinking what he could do for her, he decides to find Yeo Reum’s mother himself.

The fire on the plane and the passengers on board are all taken care of. Yeo Reum’s mom gets injured during the process, and she hears someone claiming to be Yeo Reum’s friend help her out. After hearing this story, Yeo Reum looks around to find Soo Yeon, but he is nowhere to be found.

When Yeo Reum asks Soo Yeon whether he likes her or not, he tells her the truth. Yeo Reum becomes dumbfounded and does not know what to do. Later on, she meets Eun Seob and tells him what has happened. Meanwhile, In Woo tells Seo Goon that it is impossible that Soo Yeon is living a normal life.

During a meeting, In Woo brings up the topic about Soo Yeon and his support device. He asks Moo Ja to look into In Woo with the excuse that the majority’s safety is more important than an individual’s privacy. Seo Goon tells Soo Yeon about this and warns him to stay low for the time being. When Soo Yeon asks In Woo why he did it, he tells him that he’s going to take him down.

Seeing that Yeo Reum does not have a place to stay for the night, Soo Yeon offers his place. At first, she reluctantly agrees, and they arrive at his house. While Soo Yeon goes into his room to get changed, Yeo Reum decides to secretly pack her belongings to go to a sauna but gets caught by him.

Seo Goon puts Soo Yeon in charge of persuading In Woo to allow their team to have a lounge area for the workers, and he obeys her. Meanwhile, Eun Seob visits T2 to eat with Yeo Reum. While waiting for her, he overhears a group of employees gossiping about Yeo Reum and Soo Yeon.

After Soo Yeon says something that Yeo Reum’s father used to say, she asks him whether he knew her dad or not. He tells her that he has known her father for a long time but didn’t mention it to her in case she did not have a good relationship with her father. Meanwhile, Young Joo’s doorbell rings, and she goes out only to find Yeo Reum standing awkwardly with her luggage.

While chasing a drug broker, Young Joo gets hurt. Instead of chasing the culprit, Dae Gi runs to her and asks her how critical her injuries are. However, Young Joo gets upset and asks him whether he would have done the same if she were a guy. Meanwhile, a fight breaks out between a passenger and a security check employee. In Woo tells the employee to beg in front of the passenger until he decides to forgive him. However, Seo Goon feels differently.

Soo Yeon saves Moo Ja from getting beaten up by the group of brokers whom he chased down before. However, one of the men electrocutes Soo Yeon, and he falls to the ground. Moo Ja sees electric currents running through Soo Yeon’s body. Meanwhile, Yeo Reum calls Soo Yeon to see if he is okay, but he does not pick up.

After the incident, Soo Yeon is told not to use the synthetic arm until he fully recovers since it could worsen his current condition. However, he finds himself missing Yeo Reum too much and decides to leave the house while wearing it. Meanwhile, Yeo Reum finds out that an old man’s son left his own father in Korea.

Mister Jang strongly suggests that Soo Yeon needs to take a rest for a while, but Soo Yeon insists on going back to work. At the airport, Yeo Reum runs into a high school classmate Min Jung who used to bully her. Min Jung who now works for a travel agency plans to take advantage of Yeo Reum to get some benefits for her work. In the meantime, Dae Gi loses his radio while quarreling with a pickpocket in the airport.

Min Jung continues to blackmail Yeo Reum, and Seo Goon gets to hear their conversation. A man who has found Dae Gi’s radio keeps fooling around him without returning it. And Dae Gi is told to be on stand-by until he finds the radio back. Meanwhile, Eun Seob tells Soo Yeon to share his conditions with Yeo Reum, but Soo Yeon says he want to keep it secret from her.

Soo Yeon thinks he has found out why his support device malfunctions. And he seriously considers quitting his job at the airport. Yeo Reum finds a man who has Dae Gi’s radio. In the meantime, someone in the office happens to see Mr. Lee receive an envelope from those who are in charge of managing the vans and taxis and spread a rumor that Mr. Lee is bribed.

Director Kwon gets to know about the bribe Mr. Lee received from those who are in charge of managing the vans and taxis. He gets furious and questions Mr. Lee about what’s inside in the envelope. Meanwhile, Yeo Reum sees a man threatening a female reception staff with a weapon in the airport. She tries to sort out the situation.

The man who threatened the information desk staff and ended up hurting Yeo Reum runs away. Dae Gi and Young Joo get scolded by Moo Ja for losing him. Soo Yeon finds out that Yeo Reum got injured and was taken to a hospital. He feels frustrated with the fact that there’s nothing he can do for her because he’s disabled sitting on a wheelchair. Soo Yeon decides to take revenge on the man who hurt Yeo Reum.

Yeo Reum, Dae Gi, and Young Joo come to the police station to testify about the incident at the information desk as witnesses. After the testimony, the three and Soo Yeon spend time together having a meal and dessert and riding a rail bike. In the meantime, Moo Ja continues to suspect that Soo Yeon was the one who beat up the criminal with his power.

Moo Ja comes to visit Mr. Jang and ask a few questions about the device Soo Yeon is wearing. In the meantime, Mr. Gong of Passenger Services gets involved in a scandal that he is abusing his power and forces subcontractors to have a drink with him after work. To make things worse, Mr. Gong’s daughter happens to visit his office on the day Mr. Gong is questioned by the Internal Affairs Team.

Mr. Jang suggests that Soo Yeon get a thorough medical check-up because his inflammation level came out too high, but Soo Yeon refuses, saying that he is perfectly fine now. Meanwhile, Soo Yeon happens to see In Woo having a talk with Director Jo who made Soo Yeon severely injured in the past. Soo Yeon gets disappointed that In Woo is still associating with Director Jo.

Incheon International Airport is put on emergency alert as it gets surrounded by heavy fog. Flights from and to the airport are delayed or canceled, and passengers are stuck in the airport. In the meantime, Yeo Reum finds out that Soo Yeon is in serious condition and he's just pretending to be fine.

Because of the heavy fog, all the passengers are stranded at the airport. All the staff at the airport is busy taking care of the delayed passengers. Meanwhile, Soo Yeon shows his resentment towards Mr. Jang for telling Yeo Reum about his condition. When Soo Yeon spends time alone in a park, Director Jo and his subordinates approach Soo Yeon.

Soo Yeon fights against Director Jo and his subordinates. Director Jo gets shocked to see what Soo Yeon is capable of with his arm. In the meantime, Moo Ja keeps trying to find out who’s behind In Woo, and Seo Goon wants to know why Moo Ja is asking around about In Woo.

Soo Yeon gets nose blood in front of Yeo Reum. Yeo Reum tries to help Soo Yeon, but he refuses Yeo Reum’s help and goes to a restroom alone. Then, a group of thugs follows into the restroom. One of them looks familiar to Soo Yeon, and they take Soo Yeon somewhere. When Security Services staff arrives at the mensroom, Soo Yeon is not there. Then, everyone including Moo Ja and In Woo starts to find Soo Yeon.

Soo Yeon submits a resignation after deciding to leave the airport. Yeo Reum is heartbroken to hear about it from Seo Goon and tries to hold back Soo Yeon from leaving. However, Soo Yeon seems persistent with his decision.