Los habitantes de Seúl observan sorprendidos un extraño objeto que cuelga de un puente sobre el río Han. El objeto es, en realidad, una monstruosa criatura mutante que al despertar devora a todo aquel que se cruza en su camino. En medio de tanto horror, la criatura mutante rapta a la hija del dueño de un quiosco que vive felizmente a la orilla del río. Mientras el ejército fracasa una y otra vez en sus intentos de destruir al monstruo, este hombrecillo anónimo y su familia intentan recuperar a su hija.

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.