Souta Tawara is a web designer working in Tokyo. When he visits his family's Udon place in his hometown Kagawa Prefecture, he discovers a young boy. Upon confronting the boy, Souta soon learns his secret and decides to quit his job in order to take care of the boy, Poko. The daily adventures of the two slowly enfold as Poco energetically navigates his way through Kagawa, the "Udon Kingdom," along with Souta.