Keiko Yasuda witnesses her neighbor, Namiko Todaka, committing adultery while walking past Todaka's house one afternoon. Knowing this, Namiko constantly harasses Keiko so that the latter would keep what she saw to herself. Namiko also encourages her daughter, Yuria, to bully Haruka, Keiko's daughter, at school. Haruka seeks revenge against Namiko after watching her mother constantly suffer and after having suffered under Yuria's bullying as well.