The narrative is set in the distant future, following the decline of civilization. Hiyoko is a high school student aiming to gain admission to an art university. She flees her home after her father attempts to discard her mother's keepsake drawings. She discovers a slum situated within a stadium and encounters Akira, the leader of the street children. The police attempt to demolish the stadium to beautify the city. To resist the demolition, the residents of the stadium plan to host a street-art event called "The Asylum Session". Hiroko takes charge of a giant painting on the stadium.