A teenage girl is captured by a giant mutated squid-like creature that appears from Seoul's Han River after toxic waste was dumped in it, prompting her family into a frantic search for her.

Mr. Kim is jobless, lost in debt and has been dumped by his girlfriend. He decides to end it all by jumping into the Han River - only to find himself washed up on a small, mid-river island. He soon abandons thoughts of suicide or rescue and begins a new life as a castaway. His antics catch the attention of a young woman whose apartment overlooks the river. Her discovery changes both their lives.

People binge eat and suffer from extreme thirst, which leads them to go crazy for water. They cannot control themselves because they are brainwashed by a parasite.

Under the Sungsan Bridge, in a waterside stand by the Han River, a poor and tired-looking father and daughter, Jae-mun, and In-seon, are arguing the generation gap over whether to buy boiled eggs or instant crackers. The stand owner Hee-bong hears Jae-mun suddenly declare that boiled eggs float.