The story begins with the fateful encounter between Asagi Sora (Hirose Suzu), who grew up in the countryside of Kyushu, and Umino Oto (Nagase Ren), a young man who dreams of becoming a musician. The two, who thought they would never meet again in their lives, started living together in a house in Tokyo. They had already fallen in love, but they had not started dating, as if they were in the ambiguous and dazzling "twilight" between day and night.