Lee Dae-ho is a single father and manager of Tower Sky, a 120-story luxurious twin-tower building complex located in
Yeouido,
Seoul. He promises to spend
Christmas Eve at an amusement park with his daughter Ha-na, but has to call it off when an upcoming party requires him overseeing the preparations. Attendees include tenants of the Tower Sky complex and its owner and president, Mr. Jo, as well as VIPs and South Korean politicians. Jo and Mr. Cha, the Tower Sky's safety section head, decide to host the party despite the forecasted strong winds and the faulty water sprinklers of Riverview Tower, one of the two towers. That night, two helicopters are sprinkling snow near the party when
updrafts cause the crafts to lose control. The lights attached to one helicopter crash into the glass bridge connecting the two towers, while the other crashes into the 63rd floor of the Riverview Tower. The building catches fire because of leaking fuel, and pandemonium erupts as people attempt to flee. A team of firefighters arrives at the scene, led by Captain Kang Young-ki, who joined at the last minute despite being off-duty, including Sergeant Oh Byung-man and rookie fireman Lee Sun-woo. The squad enters the building when they bump into Dae-ho, who is frantically searching for his daughter, unaware that she is taking shelter inside the Chinese restaurant alongside Mr. Cha and Yoon-hee, Dae-ho's romantic interest, among other survivors. Dae-ho leads the firefighting team through the quickest path to the server room where the helicopter crashed, and Young-ki hands him a radio and an oxygen mask so that he can go search for his daughter. They reach the server room on the 63rd floor, but can't extinguish the flames, even with Young-ki's resolute but risky maneuvers. In an attempt to stop the fire from spreading, Jo decides to activate the firewalls, leaving Dae-ho, who finally reunited with Ha-na and the rest of the survivors, as well as many other people, trapped within the blazing floors. The firefighters attempt to destroy the firewall leading to the restaurant to free them, but the walls around the restaurant crumble in around itself, causing the entire floor to collapse. Dae-ho, under Yoon-hee's suggestion, directs the trapped survivors to jump onto the
gondola in order to escape, but an elderly couple perishes during their descent, and Young-ki
euthanizes a critically injured victim using
morphine. Dae-ho's group tries to escape to the other tower, the Cityview Tower, by crossing the skybridge between them, but the structure gives way and Cha falls to his death, with Ha-na and Sun-woo barely managed to escape. The Riverview Tower then starts to buckle because of the fire damaging the structure
due to its intense heat warping the building's steel frame, and Fire Commissioner Jang decides to
demolish it to avoid it toppling over the other tower or the
Yeongdeungpo District. He orders everyone in and around the complex to evacuate, and Young-ki uses Dae-ho's fingerprint access to discharge the tower's water tanks in order slow down the rate of collapse. Young-ki and Dae-ho then ride the freight elevator in free-fall to quickly descend to the surface, and alongside pregnant woman Nam-ok, they manage to climb out before the elevator slams into the basement, trapping Yon-hee and Byung-man and leaving them slowly
asphyxiated. Dae-ho voluntarily goes back inside Tower Sky along with Young-ki and his crew to rescue the trapped survivors. They leave the survivors on the storm drain and set out to detonate the rainwater storage tanks, hoping the fast-moving current will send them straight towards the
Han River before the tower collapses. However, Young-ki loses the detonator before reaching the survivors. Young-ki then sacrifices his own life by manually detonating the explosives, and the resulting rushing torrent carries the group towards the river, right as the firefighters blow up the Riverview Tower. The survivors are pulled out from the water by the rescue team, and Sun-woo and Byung-man salute their fallen captain. Before the
closing credits, a white chocolate cake, which was meant to be delivered to Kang Young-ki, is seen in an empty display case at the now-empty
bakery. An aerial shot shows the
63 Building and the remains of Tower Sky, now consisting of the single 120-story Cityview Tower, with their surroundings covered in thick dust from the demolished Riverview Tower. ==Cast==