Lazy food stall operator Park Gang-Du's (Song Kang-ho) daughter Hyun-seo (Go Ah-sung) is grabbed by the beast and dragged away. When she makes a desperate phone call suggesting she may still be alive the Korean authorities prove useless and the whole family resolve to try and find her, but first they must escape the quarantine they've been placed under.
Bong Joon‐ho's monster movie is a mix of vaguely slapstick comedy with the Parks running about evading the authorities in slightly unbelievable ways and straight up monster horror as the creature regurgitates victims into the pit where Hyun-seo is trying very hard not to be noticed by it.
It feels rather of its day with creature effects that were lauded at the time but seem a bit "pasted in" nowadays. They do at least go straight for an onscreen rampage after the establishing scenes rather than hinting at the creature in the dark for half the movie. There's some politics about US influence in Korea but mostly it's taking a punt at the Korean authorities for being rubbish and corrupt.
Decent as you'd expect from Bong Joon-ho and that one scene at the end cemented Bae Doona as a badass forever, 7/10 a good non-Hollywood creature feature but has aged slightly poorly.