Who’s Who in The Great Flood: The Ultimate Cast and Characters Guide

South Korea is about to drop a sci-fi disaster movie that goes bigger than most: a world-swallowing flood, a single apartment building turned into a sinking pressure cooker, and a rescue that might not be as simple as it looks.

What is it?

'The Great Flood' is an upcoming South Korean sci-fi disaster film from director Kim Byung-woo, who co-wrote the script with Han Ji-su. The headline premise is simple and loud: a catastrophic deluge that submerges pretty much everything. But the movie clearly wants to be more than a wet survival run. It folds in sci-fi ideas, moral choices, and the gnarlier side of rescuing people when tech and desperation collide.

The setup

The action zeroes in on one heavily hit apartment building where an AI researcher, Gu An-na (you’ll sometimes see it styled as An Na in official materials), is trapped with her young son. A security specialist named Son Hee-jo shows up to save her — and that kicks off the big question: why her, and who sent him?

'A great flood has hit planet Earth. People, including An Na (Kim Da-mi) and Hee Jo (Park Hae-soo) struggle to survive in their apartment building, which is sinking into the water. An Na is an AI development researcher and Hee Jo belongs to a human resource security team, who is trying to save An Na from the disaster. But why is Hee Jo trying to save An Na and who is behind it?'

That 'human resource security team' label is one of those oddly specific titles that sounds corporate, but in context think more people-protection unit than office HR.

Underneath the disaster surface, the film is clearly playing with themes: last chances for humanity, tech as salvation or threat, and the ethics of choosing who gets saved when time and oxygen are running out.

The cast (stacked, with some intriguing question marks)

• Kim Da-mi as Gu An-na — an AI researcher whose expertise and choices matter when everything starts sinking; trapped in her building with her son.
• Park Hae-soo as Son Hee-jo — on a people-security detail and actively trying to extract An-na; expect action, tension, and possibly a bigger agenda.
• Kwon Eun-seong as Ja-in — An-na’s son, stuck alongside her and pulled into Hee-jo’s rescue orbit.
• Kang Bin as Mi-jung — another resident trying to get out alive.
• Jeon Yu-na as Lee Ji-soo — one of the neighbors riding out the crisis.
• Plus: Kim Kyu Na and Jung Min Joon as residents of Apartment 304; Eun Su; Jung Shi Hoon; and Lee Jae Woong in an undisclosed guest role.

Release plan

The film had its world premiere on September 18, 2025 at the 30th Busan International Film Festival, slotted into the Korean Cinema Today – Special Premiere section. For everyone else, it starts streaming globally on Netflix on December 19, 2025. Runtime is 108 minutes.

If you’re in the U.S., you’ll need a Netflix plan: $7.99/month for Standard with ads, $17.99/month for ad-free Standard, or $24.99/month for Premium.

Why keep an eye on it

Early chatter is calling this one of the most ambitious Korean disaster movies in a while. The premise isn’t subtle (end-of-the-world water levels rarely are), but the tight focus on a single building and a rescue with murky motives makes it feel more thriller than spectacle. If Kim Byung-woo sticks the landing, expect high-tension set pieces, moral hand grenades, and a few revelations about why An-na matters when the world goes underwater.

Circle December 19 if you want a holiday season watch that swaps snow for a rising waterline.