The Host is a monster movie that transcends the horror genre. There are several scary scenes, to be sure (including a fantastic crowd chase scene), but there are also moments of political conspiracy, family dysfunction, medical melodrama, and humor. During one scene, a family mourns over the supposed death of a young girl, but their mourning devolves into an absurd, slapstick fight. Since I'm unfamiliar with Korean culture, I didn't understand if their mourning was proto-typical or merely played as a comic device for the film. I felt guilty laughing during the scene, but only a little. No matter - I've always been a fan of monster films, and The Host certainly delivered on many levels.
On orders from his American superior, a Korean mortician dumps "dirty" formaldahyde down the drain, pipes that lead directly to the Han River. Several years later, a beast rises from the river and starts to hunt, prefering people above any other creature. The monster looks like an elongated fish with legs, but it's much more than that. It's truly a wonder to behold, and certainly the best film monster since Alien. The creature grabs a young girl, dragging her to its lair in the city sewer system. The film focuses on the family of this girl, and their struggle to bring her back to them. If you're in the mood to see a film involving family melodrama, political intrigue, killer chase scenes, and a hideously beautiful monster, go rent The Host.
You can read Jim Emerson's review, on Roger Ebert's site, here.