Kyoko Hori is a bright and popular high school student, in contrast to her classmate Izumi Miyamura, a gloomy and seemingly nerdy glasses-wearing child. Hori is a homebody who dresses down and looks after her younger brother Souta when she is not at school. She takes every attempt to hide this from her classmates. Souta was assisted by someone with numerous earrings and tattoos, as well as a punk-styled look, when he came home with a nosebleed one day. The entity recognizes her and introduces himself as Miyamura. They agree to keep their true identities concealed from their peers, but they begin to relate to each other as friends and then as a couple.