A 17-year-old high school girl known for her intelligence and expertise in everything. After living apart from her family, she works hard to make ends meet. In her spare time, she spends time in the virtual world "Tsukuyomi," admiring her idol, Runami Yachiyo. She has a talent for composing songs, but unfortunately, she gave up for some reason. Until she meets Kaguya, a mysterious girl from the moon, who then changes her entire life.