The story begins when a U.S. military official orders the disposal of formaldehyde into the river, which causes a chemical reaction that mutates a creature living in the water. The creature, a gigantic and horrifying amphibious beast, emerges from the river and begins to terrorize the city of Seoul. It causes widespread panic, destroying everything in its path.

In the midst of this chaos, the Park family, led by the patriarch Hie-bong (Byun Hee-bong), faces a devastating personal tragedy when their daughter, Hyun-seo (Go Ah-sung), is taken by the monster. The family members—Hie-bong, his son Gang-du (Song Kang-ho), daughter Nam-joo (Bae Doo-na), and son-in-law Pyeong-ho (Park Hae-il)—set out to rescue Hyun-seo, who is being held captive in the monster’s lair.

As the family confronts both the monstrous creature and the government’s ineffective response to the crisis, they also discover that they are up against far more than just the beast itself. There is a deeper conspiracy involving the government and foreign powers, with the monster being linked to environmental negligence and political corruption. As the family members go to extreme lengths to save Hyun-seo, they must also fight against the chaos, confusion, and incompetence surrounding the monster crisis.

The Host is notable for its combination of thrilling monster action and its subtle social commentary, touching on themes such as environmental destruction, government incompetence, and familial bonds. The film’s creature, though a central antagonist, serves as a symbol of humanity’s hubris and the unintended consequences of scientific and environmental irresponsibility.

With a strong emphasis on character development, the movie provides a deeply emotional storyline, focusing on the lengths a family will go to for the ones they love. The special effects are impressive, especially for the time, making the creature terrifying and believable. Bong Joon-ho masterfully blends genre elements, crafting a monster movie that is both an action-packed thriller and a poignant drama about the survival of family and the fight against overwhelming odds.

The Host received widespread acclaim for its unique combination of horror, satire, and social relevance, and it has become a classic of modern monster cinema.