The Great Flood (film)

The Great Flood (Korean: 대홍수) is a 2025 South Korean science fiction disaster film co-written and directed by Kim Byung-woo. Starring Kim Da-mi and Park Hae-soo, the film depicts the desperate struggle of those who have pinned their hopes on humanity's last days in a flooded apartment building.^[2][3]

The film had its world premiere at the 30th Busan International Film Festival in the Korean Cinema Today - Special Premiere section on September 18, 2025.^[4][5] The film was made available for global streaming on Netflix on December 19, 2025, following its festival release.^[6]

An AI researcher named Anna, recently widowed, wakes up and finds that her apartment is flooding. While climbing the stairwell of the thirty-floor building with her six year-old son Jain in order to escape the rising water, amidst a throng of other residents, she receives a phone-call from the United Nations explaining that a team of agents has been sent to extract her and her son by helicopter. Nearly drowning from an incoming wave, she is rescued by an agent named Heejo, who explains that the United Nations had known for years of an asteroid which would strike the North Pole, causing a flood which would exterminate humanity. Instead of making the news public, they built a secret space-station and funded cutting-edge projects to engineer new human bodies and minds, Anna's employer being tacitly part of that project. Anna is swept off the corridor into the water by another wave. She swims back to the building and hears a girl trapped in an elevator, but is unable to open the door, and is forced to abandon her when the water rises. When Anna, Jain, and Heejo reach the roof, a SWAT team grabs Jain and extracts his consciousness with a machine. It is revealed that Anna had not given birth to Jain, but rather, Jain was an artificial baby whose mind was based on Anna's AI software, whom Anna agreed to adopt as part of a process to improve the software. The official leading the SWAT team tells Anna that only she and the disk containing Jain's consciousness may board the helicopter whilst the rest of them are to stay behind and drown. Heejo is killed by the SWAT team, presumably for complaining. Anna is later placed in a rocketship and sent to a space-station, but on the way the ship is struck by debris, seemingly killing everyone.

Anna suddenly wakes up again in her apartment with the flood-water rising. She tries to climb the stairwell with her six year-old son, going through the same events as before. However, she is separated from Jain by an incoming wave. As she swims around to look for Jain, she is struck by a floating car, seemingly dying, but she wakes up in the building with Heejo having resuscitated her. The two of them comb through the building looking for him. On the way, Anna passes the elevator from before and drowns while trying to rescue the girl, named Jisoo. Somehow a new timeline is created, and she is able to open the elevator doors using a broomstick as a lever. Jisoo tells Anna that Heejo was kidnapped by two young men who were looting the building. Anna searches for the two looters and is attacked by them and almost killed, but defends herself long enough for Heejo to come to her rescue, who used Jisoo's key to open the door (it was her apartment being looted). Jisoo decides to stay behind to die with her grandparents. Heejo decides to have two SWAT agents subdue Anna and take her to the helicopter, but Anna, having regained some memories of past timelines, tells Heejo that the SWAT agents will kill him next. Anna and Heejo fight through several SWAT agents. Checking her phone, Anna sees that Jain has sent her a painting of the first timeline where Anna was forced into the helicopter, leaving Jain behind. Moreover there are thousands of similar paintings from previous timelines all saved on her phone. Anna is finally reunited with Jain on the roof, and they drown together as a large wave descends upon them.

It is revealed that, in the first timeline, the only real one, Anna was mortally wounded by the debris, and upon being rescued by another space-ship, asked for her mind to be uploaded into the computer-system for creating artificial humans. The thousands of other timelines were simulations of the last hour of Anna's life which were conducted in order to replicate the emotions felt between a mother and son, for the purpose of refining the AI system. Within each timeline, Anna and Jain were deliberately separated so that Anna would need to undergo the travail of looking for him, and it required thousands of rounds for Anna to retrieve her son successfully, thereby producing the data needed to conclude the simulation. In the space station, new artificial bodies are created for Anna and Jain, and they are allowed to continue their lives as mother and son.

• Kim Da-mi as Gu An-na^[7]
• Park Hae-soo as Son Hee-jo
• Kwon Eun-seong as Ja-in
• Kang Bin as Mi-jung
• Jeon Yu-na as Lee Ji-soo
• Eun Su as Pregnant woman
• Jeon Hye-jin as Lim Hyeon-mo
• Park Byung-eun as Lee Hwi-so
• Lee Hak-joo as Shin Ga-won

In June 2022, the company Fantasy Light enters into discussions with Netflix about the disaster film The Great Flood by Kim Byung-woo, which would mark the return of actress Kim Da-mi in the lead role.^[8]

In August 2022, Netflix confirmed the production of the science fiction disaster film, with the screenplay by Kim Byung-woo and Han Ji-su. Kim Da-mi and Park Hae-soo were confirmed to play lead roles.^[9]

Filming started on July 1, 2022, and ended on January 5, 2023.^[10]

The Great Flood's world premiere was on September 18, 2025 in the 'Korean Cinema Today - Special Premiere' section of the 30th Busan International Film Festival.^[11]

Streaming started on Netflix on December 19, 2025.^[12]

On the review aggregator website Rotten Tomatoes, 47% of 15 critics' reviews are positive.^[13]

• The Great Flood at IMDb 
• The Great Flood on Netflix
• The Great Flood at HanCinema