Well, if ya ever happen to find it again...
Ok, I think I remember it now. The idea was based off a rhythm game I'd playing on mobile for a while. The idea was that the world heavily relies on music to functions. It was pretty much the source of power and without it, the world would be under a colorless silence, and those who get caught in it's effect would be trapped in a monotone state. They become unaware of anything and anyone around them and it eventually leads to their death. To prevent this, beings known as Songsmiths and Conductors keep the world functioning with their music, wether it be through singing or just playing a single instrument. Songsmiths and Conductors often work together, with the Songsmiths creating the music for the Conductor to play.
One day, however, a mysterious force appeared and music began to die down and so did the world. Songsmiths and Conductors were hunted and killed off one by one. It drove people crazy as well, many of them believing that it was the Songsmiths and Conductors who were behind all of the madness and they began killing them off as well.
It had been many years since this happened. The world was trapped in it's empty, colorless state and there are few Songsmiths and Conductors left. A lone Conductor, who once a beautiful voice that could bring life back to anything and loved to play violin, had gone mute due to an unpleasant encounter with people who blamed them for the world's state months ago. Since then, the Conductor lived alone, never playing her violin for anyone but herself. The Conductor then meets a Songsmith who'd been traveling the world in search of what caused the madness in the first place. The Songsmith tries to get the Conductor to assist him, but she refused, having no interest in helping people. Eventually, he manages to convince her to join him and so began the story of an adventurous Songsmith, a Conductor who seems to refuse to play for him, and their journey to fix the world.