Who's in the cast:
Hyun Bin as Ri Jeong-hyeok
Son Ye-jin as Yoon Se-ri
Kim Jung-hyun as Gu Seung-joo/Alberto Gu
Seo Ji-hye as Seo Dan
Chairman Yoon Jeung-pyeong of Queens Group was arrested for violating the Act on Aggravated Punishment of Economic Crimes. After 283 days he's being released on probation. The press has been going wild with his recent announcement of stepping down. All eyes are on who will become the heir between his eldest son Yoon Se-jun and his second eldest son Yoon Se-hyeong. The two brothers and their wives are constantly fighting to get one step ahead. Chairman Yoon also has a daughter Yoon Se-ri, but she has been estranged from the family for years. She left her family ten years ago and started her own successful company.
With the news of her father's release, she attends the family dinner upon her father's wishes and to congratulate his release. Within minutes of entering the dining room, Chairman Yoon announces that he wants Se-ri to take over the company. He's impressed by her ability to start her own company and is confident in her ability. Her brothers and mother are completely against it. The Chairman plans to make the official announcement at the shareholders' meeting.
Se-ri's company just recently launched a new sports line. She decides to test out the equipment herself by going paragliding. Knowing that she'll be busy starting tomorrow morning with Queens Group, she wanted to take the chance to fly high into the sky. While gliding in a sky she suddenly sees a tractor flying past here and a giant tornado whirling her way.
While patrolling the Korean Demilitarized Zone (DMZ), Company Five of Civilian Police Battalion led by Captain Ri Jeong-hyeok arrested grave robbers. Captain Ri promised to punish them greatly for digging up cultural artifacts after crossing the Southern Limit Line. The State Security Department officer, Lieutenant Commander Cho Cheol-gang tries to subtly tell Captain Ri to be lenient because it must be a misunderstanding. Captain Ri refuses to take it lightly because he made a promise to the captain of the South that they'll be severely punished. Lieutenant Commander Cho makes a promise to him as well, that he never goes easy on anyone regardless of their ranks. If he commits any acts that may threaten their army's security and get caught by him, he'll be finished on the spot. He playfully adds, "But of course you wouldn't do anything like that."
Se-ri wakes up the next morning dangling from a tall tree. Her gear is tangled and walkie talkie isn't working as she tries to call for help. Captain Ri happens to be patrolling the area when he hears a woman's voice calling for help. He approaches her carefully with his gun pointed at her. She happily waves at him thinking they must have dispatched the army to save her, but she notices his uniform isn't from the South. He demands that she comes down from the tree immediately and cocks his gun.
She panics and unfastens her gear causing her to fall out of the tree and directly into his arms. He drops her as he continues asking for her identification. She mentions working at a fashion company but isn't comfortable telling him her name. She welcomes him into the Republic of Korea thinking he's a defector from North Korea or a spy. He informs her that this is the DMZ on the Northern Limit Line and shes trespassing. Se-ri explains that it was a paragliding accident due to the tornado. Captain Ri tells her to explain it just like that when she gets investigated, but he'll need to tie her up. She begs him to let her just run back to save her life. As she starts running, he warns her they're in an active minefield. Before he could reach her he steps on a mine. She takes the opportunity to escape while he waits for a comrade to come help him. Since he's stuck, he gives her some useful tips to avoid mines and directions to take a right at the fork in the road. She jokes about how he's her type and if the countries reunite, let's meet under different circumstances.
First Lieutenant Park Kwang-beom works to disarm the mine under Captain Ri's foot with little to no experience. With the Captain's help, he was able to successfully deactivate it. They send a message to the others in their team to capture the South Korean lady. Se-ri continues running through the forest as the men chase her. She runs through another minefield not knowing she's escaping death by inches at a time. She continues heading straight ahead towards a fence that leads to North Korea. They all try to signal her that she's running the wrong way, but she jumps the fence anyway. They call the control tower to try to stop her, but the soldier was too busy watching Korean dramas to notice her running past him.
Back in South Korea, the news of Se-ri going missing has her family all feeling mixed emotions. Her brothers and their wives are all thrilled at a second chance at inheriting the family company. Their only concern is the stock prices dropping if news gets out and when they should determine she's dead.
The second eldest brother, Yoon Se-hyeong is convinced by his wife to focus on searching for Gu Seung-jun instead of Se-ri. Seung-jun is the man that ran away with their money and capturing him can put them back in the running as the heir now that Se-ri's gone.
Se-ri's mother feels guilty because her last conversation was of her telling her daughter not to accept the company. She accused her of taking what she can. Se-ri retaliated with her not having a mother because what kind of mother wants her daughter gone.
Company Five regroup as they blame each other for losing the woman. Captain Ri and First Lieutenant Park were dealing with the mine situation. Master Sergeant Pyo Chi-su was drinking, Staff Sergeant Kim Ju-meok was watching South Korean dramas, and Private FIrst Class Geum Eun-dong left his post. They'll all be dead if she gets caught by the State Security Department.
Lieutenant Commander Cho Cheol-gang goes into an interrogation room with the grave robbers that were previously caught. They tell him that they were successful with their findings and lets him know where they're located. Lieutenant Commander Cho lets them know that Captain Ri is no match for him and that they won't be punished. While the grave robbers were being transported in a car, an armored truck with a steel front plate rams into it fully knocking it off a cliff. A lady on the side of the road happens to witness the scene and gets killed as well.
After running and suffering all day long, Se-ri finally spots a town in the night. She applauds herself for making it back to South Korea and can't wait to get home. The town is completely dark but people are outside working. Lights turn on as an announcement for the daily exercise routine blares over a loudspeaker. Everyone in the town is doing synchronized exercises and the kids gather in lines to march to school. She notices their accent as it dawns on her that she might still be in North Korea. As a car with Lieutenant Commander Cho approaches her, someone grabs her and pulls her behind a gate. She's left looking into Captain Ri's eyes as a familiar face puts a smile of relief on her face.