Spoilers throughout.
The Prequel I Thought I Was Getting
By the time the trailer for Colony appeared, I had already put it in the wrong mental folder.
The early description I encountered placed it somewhere in the orbit of Train to Busan and Peninsula. That was enough for me to assume there was a direct connection. Perhaps it was a prequel, perhaps another outbreak story happening elsewhere in the same ruined Korea, or perhaps it would finally fill in some of the biological blanks left by the earlier films.
It turns out I was mistaken.
Colony, also known by its Korean title Gunche, is not a third instalment in the Train to Busan continuity. Director Yeon Sang-ho has described it as a separate story, deliberately distinguished from Train to Busan, Seoul Station and Peninsula. Where those films used zombies as pressure applied to human drama, this one was conceived around the infected themselves: how they move, learn, communicate and evolve. Yeon has compared its structure to an escape-room game rather than the emotional journey that drove Train to Busan.
That distinction matters because Colony is not really interested in filling out a franchise timeline. It does not want to tell us what happened on another railway line or which government laboratory misplaced the original Busan virus. Its question is stranger.
What happens when the zombies stop being an unthinking crowd?
And what happens when they begin sharing notes?
An Emergency Call Before the Screaming
The film opens with an emergency call from Seo Young-cheol, a biologist announcing his intention to commit an act of bioterrorism. He claims that he has the cure inside him and has already injected himself with it.
It is a useful opening because it gives away part of the mechanism while withholding almost everything else. Young-cheol does not sound like a man panicking over an accident. He sounds like someone delivering a demonstration. The infection is not an unforeseen disaster to him. It is an argument.
Soon afterwards, a presentation at the Doongwoori Building introduces the scientific language that will govern the rest of the film. Chains Bio is promoting research involving cellular regeneration, slime mould and shared biological consciousness. There is talk of organisms communicating through chemical signals, behaving collectively and transferring information through a network rather than functioning as isolated individuals.
This is usually the moment in this sort of film when the science becomes decorative wallpaper. There will be a few animated cells on a large screen, someone will say “mutation”, and then a security guard will be eaten near a fire door.
Colony takes the unusual step of making its scientific proposition the actual shape of the horror. The conference is not there merely to explain where the zombies came from. It teaches us how to watch them.
Young-cheol injects company chief Kang Woo-cheol. The infection takes hold. People begin convulsing, vomiting a thick white substance and attacking those around them. The Doongwoori Building seals itself into a vertical trap, and the biological sales pitch becomes an outbreak moving from floor to floor.
The premise is familiar. The operating system is not.
Science-Shaped Horror, Rather Than a Biology Textbook
I think Colony gets the science down pat, although perhaps not in the sense that anybody should use it to revise for an examination.
It gets the science right in the way good speculative horror often does. It takes several real phenomena, pushes them together, removes the sensible limits and then asks what the resulting organism might do to us.
Fungi genuinely use chemical signals, including pheromones, to communicate and coordinate processes such as mating and cellular behaviour. Parasitic fungi can also manipulate insect hosts, altering their movement in ways that have understandably provided horror writers with material for years. There are likewise genuine networks through which fungi and plants can exchange nutrients and signalling compounds, although the popular “wood wide web” metaphor tends to make those systems sound neater and more intentional than they are.
There is one small taxonomic complication. Slime moulds are not actually fungi. They are generally classified among amoebozoans or protist-like organisms, despite the fungal appearance and unfortunate name. Some slime moulds can nevertheless solve simple spatial problems, respond to changing conditions and find efficient routes through mazes without possessing anything resembling a brain.
Colony takes those ideas — chemical communication, distributed problem-solving, fungal imagery, parasitic control and swarm behaviour — and turns them into a single fictional infection. Its victims are not just being driven by hunger. They are becoming terminals in a biological network.
The infection records what each body sees. It shares successful and unsuccessful attacks. When one infected person discovers a route, recognises a weapon or learns how the survivors are defending themselves, the rest can adjust.
It is not literal science. Fungal pheromones do not upload visual memories, slime mould does not turn human beings into wireless routers, and no known infection operates like an aggressive group chat composed entirely of dead people.
But the film provides enough genuine biological scaffolding for the invention to feel thought through. It is not simply shouting “fungus” because The Last of Us made the word commercially useful again. There is an underlying behavioural concept, and the film keeps returning to it.
Musical Statues With a Firmware Update
The best image in Colony is not necessarily an attack. It is the pause.
The infected suddenly stop moving. Their heads tilt or pull backwards. Bodies tremble in synchronised stillness, as though a signal has passed through them and temporarily overridden every other instruction.
Then they start again.
The effect is somewhere between a seizure, a religious experience and a group of children playing musical statues under exceptionally poor supervision. It is also the point at which the film’s monsters become properly unnerving.
Ordinary zombies frighten us because they cannot be reasoned with. They are appetite without identity, usually moving towards the nearest warm body with the strategic imagination of damp furniture. The infected in Colony are more troubling because their failures become communal knowledge.
Every encounter trains the next encounter.
The moments of stillness therefore become biological software updates. The network is processing what has happened, consolidating information and preparing the colony to behave differently. A survivor may escape one attack using a particular trick, but that does not mean the trick will work again. Once the infected have registered it, everybody on the system knows.
The production treated this collective behaviour as a physical performance rather than leaving it entirely to digital effects. Twenty professional contemporary dancers were used to develop the infected movement, including the sudden upright postures, four-limbed running, head-back trembling and synchronised imitation of the survivors. The filmmakers described this as an unusually dance-led approach for a Korean zombie production.
That decision pays off. A computer-generated crowd can be made to move in perfect unison, but perfection is not always frightening. Human bodies attempting near-perfect unison retain small tensions and discrepancies. A shoulder arrives a fraction late. A foot drags. A neck bends at an angle that suggests a person is still somewhere inside the mechanism, even if the mechanism is no longer interested in them.
The choreography gives the infected something many contemporary screen zombies lack: behaviour worth watching.
The Building as Petri Dish
The Doongwoori Building is a particularly useful trap because it is both large and contained.
The film can move between a conference hall, laboratories, shops, corridors, stairwells, control rooms and parking areas without losing the pressure of confinement. The survivors are technically inside one building, yet the building is tall enough to feel like a small city whose districts are failing one by one.
Production designer Lee Mok-won and the art department recreated the 33-storey structure through a combination of extensive sets and real locations. A shopping complex was constructed for the production, while the fungal matter and white organic residue were spread through spaces designed to feel increasingly consumed rather than merely dirtied. The filmmakers also favoured practical environments and physical action wherever possible, using computer effects to extend the world rather than replace it.
The white mucus is important. Red blood is expected in a zombie film; white biological matter is somehow less comfortable. It looks medicinal and diseased at the same time. It suggests spores, saliva, egg sacs, insulation foam and the sort of material one might find behind a wall and immediately decide to sell the house.
The infection does not merely occupy the building. It begins redesigning it.
That is where my background as a designer probably affects the way I watch this. I am interested in how the environment changes from neutral corporate architecture into biological interface. The conference spaces begin as polished surfaces built for presentations and investment. As the outbreak takes hold, those same corridors become conduits. Walls and ceilings look less like architecture than tissue.
The building becomes a body, while the bodies become network infrastructure.
There is probably a PowerPoint presentation in there somewhere about synergy.
Kwon Se-jeong and the Value of Thinking Slowly
Jun Ji-hyun’s Kwon Se-jeong is the human centre of the film, although Colony is not especially sentimental about giving anyone a traditional heroic arc.
Se-jeong is a former professor and scientific whistleblower whose professional life has been damaged by her refusal to look away from wrongdoing. She attends the Chains Bio event partly because her former husband, Han Gyu-seong, has helped arrange a possible job opportunity. That already places her in an awkward position before the dead begin networking.
Jun returned to cinema with Colony after an eleven-year absence from feature films. The part makes sensible use of her screen presence. Se-jeong is not written as an invulnerable action figure or a genius who solves the outbreak by shouting technical vocabulary while everybody else waits. Her usefulness comes from observation. She understands that the infected are communicating before the others fully grasp the implications, and she keeps revising her interpretation as new behaviour appears.
She is the correct protagonist for a film in which information is the real weapon.
Her advantage is not that she possesses more information than the colony. She cannot. The infected have eyes and ears everywhere. Her advantage is that she can recognise the flaws created by their interconnectedness.
A human being can hold contradictory ideas, lie, improvise, misremember, mistrust the evidence and do something irrational. Most of those qualities are normally liabilities. Against a system that depends upon rapid, collective agreement, they become tactical possibilities.
Se-jeong is also connected personally to Young-cheol’s grievance. Late in the film, he reveals that her exposure of his father’s embezzlement led indirectly to his father’s suicide. Young-cheol has built an entire philosophy of collective evolution around what is, beneath the biological grandeur, an old wound and a need for revenge.
That revelation is both effective and slightly disappointing.
It gives the confrontation personal weight, but it also makes the world feel smaller. Young-cheol’s project is supposedly about remaking humanity, yet its emotional ignition lies in his resentment towards one person. The cosmic hive mind turns out to have a family grievance attached.
This is believable. People have built larger catastrophes around smaller injuries. It is simply a more conventional answer than the film’s premise initially seems to promise.
Seo Young-cheol and the Need to Be Understood
Koo Kyo-hwan plays Young-cheol as a man whose intelligence has curdled into theatrical certainty.
He is not simply trying to survive an infection he created. He wants to enter it. He presents himself as the carrier of a cure, deliberately allows himself to be bitten and eventually demonstrates a degree of control over the infected. His ambition is to stand at the centre of the colony as something more than an ordinary human being.
There is a certain pathetic quality to him, even when he is orchestrating mass death. Young-cheol talks about communication and collective intelligence, but his emotional life is built around the belief that nobody has properly understood him. The grand solution to human misunderstanding is therefore a system in which individuality is erased and nobody can withhold anything.
No privacy. No ambiguity. No lies. No self.
The director’s own statement connects the film’s collective consciousness to contemporary anxieties about artificial intelligence and rapidly shared information. Yeon describes individuality being displaced by a consciousness built from accumulated knowledge, with the infected acting as parts of one organism.
Young-cheol sees that as evolution. The film is less certain.
His colony can share information almost instantly, but it cannot decide whether the information is true. Its efficiency is also its vulnerability. It does not understand individual experience so much as consume data generated by individuals.
Koo’s performance keeps Young-cheol from becoming a generic laboratory lunatic. There is humour in his self-importance and an unnerving casualness in the way he watches his theory become physical. He often seems more interested in whether the experiment works than in the people it destroys.
The film could have used more time with him. His philosophy is compelling enough to support a denser villain, but the pace rarely allows the conversations to settle. Yeon has acknowledged that the film’s speed and structure limited the amount of background given to its characters.
Young-cheol remains fascinating as an idea. As a human being, he is only partly excavated.
The Human Colony: Siblings, Exes and People Under Pressure
The survivors are assembled less as a found family than as a set of different pressures placed inside the same container.
Han Gyu-seong, Se-jeong’s former husband, provides one of the film’s more grounded connections. His relationship with Se-jeong carries the awkward remains of intimacy without requiring the story to stop for a full romantic reconciliation. His eventual death while trying to protect a student gives the film a recognisably human sacrifice, although the speed of events means the emotional aftermath cannot linger for long.
Outside the building, Gyu-seong’s current wife, Gong Seol-hee, investigates the Chains Bio laboratory and becomes Se-jeong’s scientific partner at a distance. Shin Hyun-been has less material than Jun Ji-hyun, but Seol-hee’s work is crucial. The two women exchange information between the sealed building and the wider outbreak, gradually understanding that the monkeys used in the research are also part of the network.
Choi Hyun-seok and his sister Choi Hyun-hee carry much of the film’s emotional weight.
Hyun-seok repeatedly carries and protects Hyun-hee, who uses a wheelchair, but she is not left entirely as a symbol of vulnerability. From the control room, she gives false directions to the infected in order to save her brother and the others. Her use of information as misdirection anticipates the final strategy. She understands that the network can be manipulated before the survivors fully turn that idea into a weapon.
Her death is one of the film’s cruellest turns. Later, an infected Hyun-hee attacks Hyun-seok, and he stops resisting. He allows himself to be killed rather than continue fighting the body of his sister.
The scene works because it briefly interrupts the film’s puzzle-box momentum. There is no clever escape, no scientific solution and no last-minute rescue. The network has retained her physical form while erasing the relationship that gave the form meaning.
The film needed more of that breathing space. Its human stories are not badly conceived, but they are often presented as compact emotional instructions: estranged spouses, protective siblings, compromised executives, frightened employees, a selfish student. They perform their role in the mechanism and are then removed.
That makes Colony efficient.
It does not always make it affecting.
Zombie Monkeys. Obviously.
Then there are the monkeys.
Zombie monkeys.
WTF.
The discovery at the external laboratory should feel ridiculous, and it does, but it is also one of the film’s most useful expansions of the idea. The infection is not restricted to humans. The monkeys are test subjects, carriers and evidence that the network can organise itself across different bodies.
When one particular monkey is killed, the others freeze. The implication is that some part of the network has been interrupted or that the colony has lost a crucial point through which information was being coordinated.
There is something inherently unsettling about an infected primate because monkeys already move with a speed and bodily intelligence that human performers can only approximate. A zombie human is frightening partly because the body is damaged. A zombie monkey does not need the damage. It already has the climbing, grasping and leaping sorted.
The sequence risks becoming creature-feature excess, but it earns its place by extending the film’s central question. If collective consciousness can cross individual bodies, what else can join the network? Where does the colony end?
The answer, predictably, is not at the laboratory door.
Bodies Before Pixels
Yeon Sang-ho’s previous zombie films have always understood movement. The sprinting infected of Train to Busan did not simply run; they arrived in waves, folded over one another and turned crowds into physical pressure.
Colony changes that vocabulary.
Here, speed is only part of the threat. The infected mimic, calculate and repeat. They watch the survivors. They test barriers. They alter their posture and tactics. The dancers’ choreography gives the colony an eerie grammar, while action director Heo Myeong-haeng keeps the confrontations based in physical collision rather than abstract digital spectacle.
The make-up, supervised by Hwang Hyo-kyun and CELL, emphasises blistering, secretion and biological transformation rather than simply applying grey skin and contact lenses. The infected look wet, pressurised and in the middle of becoming something else.
Cinematographer Byun Bong-sun uses the building’s vertical scale carefully. High and wide views establish how little space the survivors control, while handheld close-ups make the outbreak feel immediate and badly organised. Anamorphic lenses and the 2.39:1 frame give the film cinematic width even when the characters are trapped in corridors and stairwells.
The film is visually strongest when it lets bodies and architecture interact. People are pushed into corners. The infected pile into entrances. Wheelchairs, doors, lifts, glass walls and sprinkler systems become parts of the action rather than background decoration.
The weakest moments are those when the scale expands and the film begins reaching towards a larger citywide disaster. The building is a better dramatic organism than the city because we understand its routes and limits. Once Young-cheol escapes with infected tactical officers, Colony briefly begins resembling the opening chapter of a sequel.
The bigger the outbreak becomes, the less particular it feels.
Electronic Panic and the Sound of the Pause
Chai Min-joo’s music avoids the emotional orchestral language that might have linked Colony too closely with Train to Busan. The score relies on abrasive electronic sounds, pulses and aggressive textures, punctuated by stretches of near-emptiness. The production notes describe a deliberate effort to alternate musical pressure with hollow silence and to vary the pace rather than simply maintain constant noise.
That approach suits a film about communication.
The score often feels less like accompaniment than system activity. It buzzes, accelerates and drops out, creating the impression that something is processing beneath the visible action. When the infected freeze, the reduction in movement and sound becomes as threatening as the attack that follows.
The film understands that silence is not always the absence of information. Sometimes it is the moment when information is being gathered.
There are occasions when the electronic scoring pushes harder than the scene needs. The film already moves quickly, and another layer of rhythmic insistence can make the experience feel breathless rather than tense. But the overall sound design gives Colony an identity distinct from Yeon’s earlier zombie work.
It sounds less like an apocalypse than a machine learning how to use bodies.
The Ant Mill and the Information Trap
The final strategy is where the film’s biological ideas and contemporary metaphors come together most neatly.
After Young-cheol escapes into the city with infected tactical officers, Se-jeong and Seol-hee recognise that the colony’s strength can be turned against it. By placing mycelial material on an infected body and feeding deceptive sensory information back into the network, they create a loop.
The infected begin pursuing the signal, following one another in a tightening circular path.
The idea resembles an ant mill, sometimes called a death spiral. Certain army ants navigate largely through pheromone trails. When the trail becomes circular, each ant follows the ant ahead, strengthening the same loop. The colony’s local rule continues operating even though the collective result is disastrous. The ants may keep circling until exhaustion or death.
Colony translates that behaviour into information overload.
The network is given false data. Because every member trusts the shared signal, the mistake is amplified rather than corrected. The infected become trapped in the certainty of their own communication.
It is difficult not to see the modern metaphor. We live surrounded by systems designed to share and reinforce information at speed. Repetition can make a claim appear reliable. Engagement can look like consensus. A network may be highly efficient at distributing information while remaining strangely helpless at judging whether the information deserves to travel.
The colony knows everything its bodies have seen.
It does not know when it is being lied to.
The overloaded infected revert to a more primitive state, stripping away Young-cheol’s imagined evolutionary achievement. He is pushed into a burning vehicle and, in a final grim joke, calls for rescue. The man who wanted to transcend ordinary human communication dies asking other human beings to hear him.
The network fails him at the only moment when he genuinely needs to be understood.
What Works, What Frays
Colony works best when its concept is visible through behaviour rather than explained in dialogue.
The stopping infected. The copied tactics. The synchronised tremors. The monkeys freezing when part of the system is damaged. Hyun-hee misleading the horde from the control room. The final ant mill.
Those are not simply plot incidents. They are physical expressions of the same idea.
Jun Ji-hyun gives the film a stable human intelligence. Koo Kyo-hwan gives it a villain who is odd enough to remain unpredictable. The production design turns a corporate building into a biological network, while the dancers and make-up artists create infected bodies that feel designed rather than merely recycled from another zombie production.
The pacing is fast without becoming completely incoherent. For much of its running time, the film moves like a game in which every failed solution changes the rules. That makes it entertaining and gives each sequence a practical objective.
The weakness is that the human characters rarely have enough space to become as complicated as the infected.
The siblings come closest. Se-jeong has personal history and moral weight. Young-cheol has a grievance and a philosophy. Many of the others remain recognisable types moving through the building: the frightened employee, the selfish survivor, the compromised businessman, the young person who must be protected.
The final revenge revelation also reduces the scale of Young-cheol’s motivation just when the film seems ready to expand it. His ideas about collective intelligence are interesting enough without tying the entire event so tightly to Se-jeong and his father.
The story also becomes less tense once it leaves the building. Containment gives the film shape. The city offers sequel potential.
Then there is the final twitch.
After Young-cheol is dead and the infected have apparently stopped, one body moves. It is the traditional assurance that the outbreak is not over, delivered with exactly the amount of subtlety one expects from a zombie film hoping not to close the laboratory permanently.
It is predictable.
It also works.
After Busan, a Different Line
The temptation is to measure Colony against Train to Busan simply because Yeon Sang-ho made both and both contain violently infected commuters, employees and people who have chosen a very bad day to enter a public building.
But the two films want different things.
Train to Busan uses the outbreak to compress family failure, class division and moral choice into a train moving towards a destination. Its zombies are terrifying, but the emotional machinery belongs to the passengers.
Colony is colder and more mechanical. It is fascinated by the system itself. The characters matter, but they are also variables inside an experiment. The building becomes a puzzle. The infected change the rules. The survivors search for errors in the network.
The nostalgia here is therefore structural rather than sentimental. The film recalls decades of corporate-laboratory horror: sealed facilities, biological presentations, access corridors, executives who believe safety procedures are for other departments, and scientists discovering that nature has not read the business plan.
There is some Resident Evil in the progression through controlled spaces, some Romero in the distrust of corporate authority, and the broader fungal memory of The Last of Us. But Colony combines those familiar materials around a genuinely distinctive infected behaviour.
That is enough to stop it feeling like a franchise leftover.
The film premiered in the Midnight Screenings section at Cannes before its South Korean release on 21 May 2026. It passed five million domestic admissions by mid-June, suggesting there is still a substantial audience for Yeon’s particular combination of mass-market horror and social machinery.
As far as the official credits indicate, Colony is an original screenplay by Yeon Sang-ho and Choi Gyu-seok rather than an adaptation of a novel or webtoon. Yeon has, however, spoken about a companion book and game being developed around the property, which fits the film’s modular, game-like construction rather well.
Whether it needs to become another universe is a different question.
One of Them Moves
I went into Colony expecting a missing chapter from the Train to Busan outbreak and found something more interesting, if not always more emotionally satisfying.
This is not the prequel I thought I was watching. It is a parallel experiment by the same filmmaker, taking the familiar image of a zombie crowd and asking what would happen if the crowd became the actual protagonist.
The science is speculative, but it has enough roots in real biological communication, swarm behaviour and parasitic manipulation to give the horror weight. The infected do not merely run faster or bite harder. They remember together. Their stillness is a form of thought.
The film has weaknesses. Some of its human beings are thinner than its biological theories. The villain’s personal grievance feels smaller than his philosophy. The citywide escalation weakens the sealed-building tension. Several deaths arrive before the relationships have been given enough room to settle.
But it has ideas.
It has bodies behaving in ways I had not seen quite like this before. It has white fungal matter turning polished corporate architecture into tissue. It has a heroine who survives by understanding that perfect communication may be its own kind of blindness.
And it has zombie monkeys.
The film ends with one infected body moving after the system is supposed to have stopped. That small twitch is more convincing than a neat cure would have been.
Networks rarely die when we think they have.
Sometimes they are only waiting for the next update.
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