Starring in the film as members of an unremarkable family thrust into the middle of extraordinary events were Song Kang-ho, Byeon Hee-bong, Park Hae-il, Bae Doona and Ko Ah-seong. A rare combination of blockbuster plot and political commentary, the film also deals with the implications of America's military presence in Korea.
Following the success of the director's previous work, Memories of Murder, The Host was heavily anticipated and hyped. It was released on a record number of screens in its home country on July 27, 2006 and broke box-office records throughout its domestic run. By the end of its run on November 8th, the film had been seen over 13 million times, making it the highest grossing South Korean film of all time, beating the previous leader The King and the Clown, which had attracted 12.3 million people. The film was released on a limited basis in the United States on March 9, 2007, and on DVD, Blu-Ray and HD-DVD formats on July 24, 2007.
The film opens with an American military pathologist commanding a reluctant Korean assistant to violate protocol by dumping over 100 bottles of formaldehyde down the drain, which leads to Han River. A few years later, two men are standing and fishing in Han River when one discovers a mutant fish or amphibian which is never shown. He releases the palm-sized creature when it bites him. Four more years later, a man commits suicide by jumping off a bridge into Han River, but not before noticing that there's "something dark, underwater".
In the present day, Park Gang-du is a seemingly slow-witted man who runs a snack-bar with his father, Hee-bong. Hyun-seo is a schoolgirl and Gang-du's daughter. Gang-du's sister, Nam-joo, is a national medalist archer who has an unfortunate tendency to hesitate, and his brother Nam-il is an alcoholic former activist who has not done much since graduating from university.
Gang-du is delivering a meal to some patrons, and sees a crowd gathering along Han River. He joins them as they stand near the side of the river and point at something under the Wonhyo Bridge. It is the creature, now grown. It drops into the water, and moves towards shore. Gang-du throws a can of beer into the water near it, and the creature grabs for the can. The other people nearby then begin to playfully toss other pieces of food to it, but the creature disappears from view. A few moments later, the creature appears on shore behind them, and begins to attack and devour people. Gang-du and an American man try to fight the creature, and successfully hit it with a street sign. The creature then bites off the American's arm. As Gang-du runs away, he sees Hyun-seo emerge from the snack bar and grabs her hand without stopping. He then stumbles and unwittingly grabs a different girl. A short distance away, he looks back and sees the creature pull Hyun-seo into the river. Gang-du then sees the monster dragging her on the opposite bank before disappearing into the water.
As the family mourns the young girl in a shelter set up for victims of the attack, government representatives in bio-hazard suits arrive and demand to know who has had direct contact with the creature. Gang-du admits that he has, and the family is forced to the hospital, where Gang-du is quarantined. The Korean government announces that the creature is not only a direct danger, but also the host of a deadly, unknown virus. Gang-du receives a phone call from Hyun-seo, who is not dead, but trapped in a sewer. She is cut off as her cellphone battery runs out. Gang-du tries to explain to others, but his explanation sounds more insane than sane to the people at the hospital. Hee-bong believes his son, and uses up his life savings so that they can escape from the hospital and rescue Hyun-seo. They are then able to obtain a truck, two non-yellow hazmat suits, weapons, and a map of the sewer system around the Han River.
The family search the sewers to no avail. They return to their snack stand at the banks of the Han river to rest for the night. They wake to find the creature watching them. Hee-bong fires on the creature, causing it to attack them and overturn the snack stand. As the creature tries to get at them inside, Hee-bong fires a shot that causes the creature to flee. Hee-bong, Gang-du & Nam-il give chase, firing wildly. Hee-bong is eventually killed by the creature, and Gang-du is captured by soldiers; Nam-il and Nam-joo escape but are separated.
In the hospital, Gang-du overhears that there is no virus: the government is merely perpetuating a charade to save face. The American scientist who lets out the secret claims that Gang-du is infected in the brain. A team of doctors perform a frontal lobotomy on Gang-du. Afterwards, a nurse mocks the seemingly brain-damaged and unresponsive Gang-du. He suddenly takes her hostage with a syringe full of his "infected" blood, and escapes to find that he is not in a hospital, but the back of a military truck on the Han River shores. He drives to Wonhyo Bridge in an ambulance.
Hyun-seo has been trapped in a deep sewer pit since she was spit out by the creature. The creature periodically drops off victims into the pit, to store for later. Hyun-seo finds all the others dead or dying except for a young street urchin named Se-ju. Nam-il goes to a college friend for help, and traces Hyun-seo's phone call. He is betrayed but cleverly escapes. Before losing consciousness under a bridge, he sends a text message with Hyun-seo's location to Nam-joo. Nam-Joo goes to the bridge, but comes across the creature. She is near enough that she has a shot, but just as she has the creature in her sights, she hesitates. The creature runs past her and she is knocked unconscious. Hyun-seo tries to climb out of the sewer by a rope fashioned from her and other victims' clothes, but the creature snatches her and places her back on her feet. The camera cuts to black as the creature pounces on her and Se-ju.
Gang-du discovers the feeding pit only in time to see the creature dashing away with a child's arm dangling from its mouth. He chases it on land as it dives into the river. Nam-il wakes to see a homeless man who has been tending to him, and with the man's help and liquor, he makes several Molotov cocktails and together they take a taxi to the Wonhyo Bridge. Nam-joo also awakes. She sees the creature and Gang-du run past her and follows them. The three siblings are led to the riverbank, where the creature attacks demonstrators protesting the government's use of Agent Yellow - a chemical weapon highly harmful to humans - against the creature (and non-existent virus). Police press back the demonstrators, trying to hold them back. The crowd finally disperses as the creature comes near to the shoreline. All three siblings meet up briefly on top of the bridge, but Gang-Du leaps from the bridge to chase the creature.
Agent Yellow is released and incapacitates the creature temporarily. Pushing through the poisonous fumes, Gang-du pulls out the two lifeless children from the creature's mouth. Hyun-Seo had grabbed the other child and had avoided being fully swallowed by grabbing onto a large tooth. The creature revives and tries to return to the river. Enraged, Gang-du grabs a street sign and begins to battle the creature. Nam-il also begins to throw Molotov cocktails at it that he had prepared previously. The creature, apparently terrified of fire, continues to flee. The homeless man whom Nam-il met appears and douses the creature in gasoline, but Nam-il accidentally drops his last bottle as he attempts to throw. Nam-joo picks up one of the lit fragments with her arrow and shoots it into the creature's eye, causing it to burst into flames, screaming in agony. The creature makes a last attempt to flee towards the protection of the river, but Gang-du finally impales it with a street sign. The movie doesn't explain why some of the protesters are shown coughing up blood from the Agent Yellow, but the main characters seem mostly unaffected by it, save some blood running from their ears. Se-Ju doesn't show any visible effects from the Agent Yellow, as well.
As Nam-joo and Nam-il cradle their dead niece, Gang-du manages to revive Se-ju. In the epilogue, we see Gang-du and Se-ju living as a family in the rebuilt and cozy-looking snack bar, sometime in the winter. One night Gang-du believed he saw something move outside. He gets his rifle but then sets it down, believing it was his imagination. A televised US Senate press release - claiming that the Korean "disease crisis" was caused by "misinformation" - is drowned out by their conversation. The child asks him to turn it off, as he finds it boring, and they eat dinner.
The monster was designed with some specific parameters in mind. The director's wishes were for it to look like an actual mutated fish-like creature, rather than have a more fantastical design. In the opening scenes of the film, two fishermen presumably encounter the creature whilst it is still small enough to fit in one of their cups; suggestive of it's humble, more realistic origins. The monster also exhibits frontal limbs similar to amphibians legs. This element of it's design seems to have been more a choice of functionality on the designers part as the monster needed to be able to run and perform certain acrobatic movements during the film. For a genre film monster, the creature's size is rather small, only about the size of a truck. Also unlike in many other monster-themed films, the creature is fully visible from early on in the film, sometimes for large stretches of time and even in broad daylight, which earned the film some critical praise.
Because of its themes that can be seen as critical of the United States, the film was actually lauded by North Korean authorities, a rarity for a South Korean blockbuster film.
The film also features a satiric portrayal of the South Korean government which is portrayed as bureaucratic, inept, and essentially uncaring. Korean youth protesters are featured satirically in the film, with a mixed portrayal, partially heroic, and partially self-righteous and oblivious. According to Bong Joon-ho, the Park Nam-il character is a deliberate anachronism, a reference to South Korea's troubled political history, which involved violent protest. "When you look in terms of this character, it's sort of like the feeling of time going backwards. [...] You could say that he is the image of the college protester back ten years ago; it doesn't exist in the present day.
The film was released theatrically in Australia on August 17, 2006. During the first half of September, 2006, it premiered in Japan, Singapore, Taiwan, Thailand and Hong Kong. It received a theatrical release in the United Kingdom on November 10, 2006. This was its first official release outside of film festivals, and outside Asia and Australia. Its American release was March 9, 2007. It was or is planned to be released in several other countries; among them are France, Ireland, Sweden, Germany, and Spain.
The Host received screenings on several film festivals. In addition to its opening in Cannes, among the most prominent were the Toronto, Tokyo and New York film festivals. The film swept Korea's Blue Dragon Awards : The Host received 5 awards, Ko Ah-seong took Best New Actress and Byeon Hee-bong was awarded as Best Supporting Actor.
The French film magazine Cahiers du cinéma ranked the film as 3rd place in its list of best films of the year 2006. The Japanese film magazine Kinema Junpo selected it as one of the top 10 best foreign films of the year 2006. (Flags of Our Fathers won the best foreign film of the year 2006.)
With a limited American release starting March 11, 2007, The Host garnered very positive reviews, with a 92% "Fresh" rating on Rotten Tomatoes. In addition it was ranked one of the top films of 2007 on Metacritic with a score of 85. Manohla Dargis of The New York Times wrote "The Host is a loopy, feverishly imaginative genre hybrid about the demons that haunt us from without and within. And Howard Waldrop and Lawrence Person of Locus Online called it "the best monster movie since Tremors.