The Great Flood Ending Decoded: The Fate of Hee-Jo, Anna and Ja-in Revealed

Netflix dropped a South Korean sci-fi thriller that starts as a soggy survival movie and pivots into a big conversation about AI, emotions, and what makes someone a parent. It is called The Great Flood, it stars Kim Da-mi and Park Hae-soo, and it hit Netflix on December 19, 2025. If you want the ending explained without the fluff, here is what actually happens and why it matters.

The setup: disaster movie on the surface, AI story underneath

We open with an asteroid smacking into Antarctica, melting ice on a terrifying scale and flooding the planet. An-na, a scientist, wakes to a world underwater and scrambles to save Ja-in, an AI child she has been raising like her own son. She works for Isabela Labs, which quietly built two prototype kids meant to help preserve humanity down the line: Ja-in with An-na, and Yu-Jin with her colleague Hyeon-mo.

Hee-Jo, a lab agent, calls in with instructions: climb to the roof, a helicopter is coming, and this extraction is supposedly crucial for humanity. He is helpful, but he is not telling An-na everything. He knows the lab intends to reclaim the kids; Hyeon-mo already ran with Yu-Jin because she saw this coming.

The Emotion Engine twist

Here is the turn: An-na and Hyeon-mo are the only people who can finish a project called the Emotion Engine, a system designed to teach AI real emotional bonds, specifically a mother-child attachment. Which, yes, quietly repositions the entire movie from survival thriller to 'are we engineering feelings?' thought experiment.

While hauling herself and Ja-in up the flooded building, An-na relives some painful history: her husband died in a car accident, and that loss hardened her resolve to protect Ja-in at any cost.

Rooftop extraction, and the split between reality and simulation

When An-na and Hee-Jo reach the roof, lab soldiers are waiting. An-na, realizing the kids are targets, hides Ja-in in a closet and promises him she will come back. The soldiers separate them anyway. Hee-Jo is shot before he can board the evac. An-na is flown out and ends up on a spacecraft tied to the lab operation. During a subsequent onboard accident, she is impaled and critically injured.

Before that accident, An-na volunteered to serve as the 'mother' template for the Emotion Engine test. Ja-in's memories are preserved to fuel the experiment. From here, the movie shifts into its second, much weirder phase.

The loop: how the simulation actually works

Inside the Emotion Engine, An-na relives the day of the flood over and over. Early on, she does not remember her promise to Ja-in or where she hid him. Failure resets the loop. Hee-Jo appears inside the sim to guide her, then fades. Over time, An-na starts retaining details between runs.

The breakthrough is simple and human: she remembers that Ja-in likes hiding in closets. On the final loop, soldiers again try to take the boy, Hee-Jo is shot (echoing real life), and An-na fights through to the roof. She finds the closet, reaches Ja-in, and tells him to dive into the rising water. She goes after him, survives, and breaks the loop.

Quick version: the end, cleanly

• Isabela Labs built two AI children, Ja-in and Yu-Jin, as part of a long-game plan to preserve humanity. An-na raises Ja-in; Hyeon-mo raises Yu-Jin.
• An asteroid triggers global flooding. Hee-Jo, a lab agent, pushes An-na and Ja-in toward a rooftop extraction, knowing the lab intends to take the kids back. Hyeon-mo flees with Yu-Jin.
• On the roof, soldiers move to seize Ja-in's memories for the Emotion Engine. An-na hides him in a closet, promising to return. Hee-Jo is killed; An-na is evacuated and later injured in a spacecraft accident.
• Before the accident, An-na volunteers to be the 'mother' model for the Emotion Engine. The rest of the movie's middle is a simulation where she replays the flood day in loops.
• She eventually remembers the closet, saves Ja-in inside the sim by getting him to dive, and breaks the loop.
• Ending: the experiment is deemed successful. An-na and Ja-in are placed into new bodies with their memories intact, loaded with other mother-child pairs, and sent back to Earth. Hee-Jo stays dead; he does not get a new body.

So... did An-na save Ja-in?

Yes and no. She fails in the literal real world. She succeeds inside the simulation, and that success is what the lab uses to 'graduate' her and Ja-in into new bodies. When we cut to the end, they are alive, reunited, and en route to Earth with other mother-child pairs. The cost: Hee-Jo's death sticks. And the big question mark: are these families saving humanity, or rebooting it according to lab parameters?

What the movie is really poking at

The Great Flood starts with walls of water and ends by asking whether a machine can learn something as messy as a mother's love. The film basically says: if you can simulate the bond and port the memories into new bodies, is that still real? It leaves you with more questions than answers, which is either satisfying or maddening depending on how much ambiguity you like with your disaster movies.

The Great Flood is streaming on Netflix (US) now.