GHOST CONCERT : missing Songs

In the year 2045, the world has forbidden singing.
The creation and performance of music, once the domain of humanity, have been completely taken over by the music app MiucS.
One day, Seria Aiba hears something she never should have: a forbidden singing voice.
Following the sound, she encounters a single ghost... a legendary figure manifested from beyond this world: a Great Ghost.
A secret organization known as TERA...
And the Spirit-Sync Requiem begins to echo.
“This is the story of how I became a ghost.”