Not the monster flick you expect

A monster movie for the 21st century, “The Host” takes familiar genre elements and then crushes them in much the same way the title creature runs amok along the Seoul riverbank it calls home. Written and directed by South Korean filmmaker Bong Joon-ho, it’s a film that will catch you leaning in one direction and abruptly pull you in another, all the while building to a surprisingly emotional climax.

On a U.S. military base in South Korea, a patronizing, intransigent American official (Scott Wilson in a cameo) orders a Korean subordinate to pour toxic formaldehyde down a drain that empties into the Han River. Years later, a mutant creature emerges from the watery depths, terrorizing the crowds along its park-like banks. It’s a fairly standard monster movie setup -- so standard that it looks suspiciously like parody.

Further tilting the early tilt toward comedy is the director’s generous use of slapstick in the opening sequences. But just when you think he’s playing it strictly for laughs, he throws in some attention-grabbing scares. Bong has a lot more on his mind than caricature.

At the center of the turmoil is the disjointed Park family. Father Hee-bong (Byun Hee-bong) runs a food stand beside the river with his ne’er-do-well eldest son, Gang-du (Song Kang-ho). Another son, Nam-il (Park Hae-il), is an unemployed university grad, while daughter Nam-joo (Bae Doo-na) is a competitive archer. Gang-du has a precocious teenage daughter, Hyun-seo (Ko A-sung), whose mother ran off after giving birth to her.

The family is introduced in humorous, fairly broad terms, but Bong slyly develops the characters as the film evolves, shedding its popcorn veneer to become something more complex. The transition isn’t seamless and the pace noticeably slows as the emphasis shifts to the family’s damaged relationships -- even as they attempt to hunt down the monster.

However, this unflappable tempo that dominates the movie’s midsection succeeds in allowing each character the space to assert him or herself and earn the emotional currency that makes the finale so affecting. Young Ko is particularly impressive in her intensity.

The script is laced with political jabs that include a solid broadside at the perceived paternalism embedded in U.S.-South Korean relations. Bong is also concerned with South Korea’s social structure -- poking fun at the soullessness of salarymen while championing the working class -- and it’s no surprise that he studied sociology at the University of Yonsei.

With a subversive streak as wide as the Han and a title open to interpretation, “The Host” confounds our expectations while providing top-notch entertainment. For Bong, the monster movie is an ample vessel, one that he can fill with social criticism while discovering exuberant amusement in the process.

kevin.crust@latimes.com

“The Host.” MPAA rating: R for creature violence and language. Running time: 1 hour, 59 minutes. In general release.