On the banks of the Han River in Seoul, a dysfunctional family lives a quiet life until their world is turned into chaos by the appearance of a strange creature, the result of an irresponsible chemical waste dump. This monster, combining mutant factors with an evident sense of hostility, terrifies the population and, in a heartbreaking twist, kidnaps young Hyun-seo, the family's daughter. Disquiet takes hold of her loved ones, who, desperate to save her, become protagonists in an emotionally charged tournament of the brave and the vulnerable.
The father, a man who has been a loser in life, the mother who has always remained strong, and the brother with aspirations of being a hero, embark on a secret mission. As the city plunges into panic and authorities struggle to find a solution, the family delves into a labyrinth of intrigue and confrontations, facing not only the monster but also the mechanisms of the government and military forces attempting to control the situation.
With a mix of thrilling action, moments of comedy, and a deep reflection on familial pain, this story reveals the struggle for survival and the resilience of those who refuse to give up. As the protagonists uncover dark secrets, it becomes clear that true monstrosity does not always reside in physical detachment, but within the human being itself.