The year is 2045. Singing is forbidden, and an AI system called MiucS creates music in place of people. Seria Aiba, a high school girl who can see spirits, lives quietly under these rules—until one day, she hears a real human voice singing. Following the song, Seria discovers the source: a ghost. Now Seria must decide whether to stay silent or risk everything to bring music back to the world.

Sisters Fuu and Rui used to be close, but have been a bit distant from each other recently. One day, Fuu encounters a mysterious spaceship and gains magical powers. At that same time, Rui also gains magical powers, and both transform into the adults they dream to be. The sisters' powers come with two conditions: their magic powers can only be used in one year, and no one must know about it. Unaware of each other's secrets, Fuu and Rui become active as idols.