Upon transferring to his hometown school, Okano Makoto enjoys ordinary yet joyful days with his sister, Hinata, a playful classmate named Tachibana Tsutomu, Tsutomu's friend Shikouin Kasumi, and other companions. One evening, Makoto is drawn to a familiar harmonica tune echoing through the school, leading him to the rooftop where he reunites with his childhood friend, Narukaze Minamo, after years of separation. As they navigate school life together, concealing their true emotions, Makoto and his friends embark on a series of adventures in a mysterious town, where their intertwined stories are set to unfold.