The demise of civilization does not originate from war, nor does it originate from plague.
Thirty years ago, a low-frequency sound wave called a "resonance" surged from deep within the Earth's crust. It is not fatal and does not hurt people, but it will slowly erode people's memory - first, words, street signs and book pages become meaningless lines; then language, you can hear the sound but not understand the meaning; finally, even "who I am" is forgotten, leaving only a body that can still walk. These people are called "dumb people".
The survivors built settlements out of resonance-isolating materials. Materials are being consumed.
There is a profession in the settlement called "sound picker" - a person who specializes in sneaking into ruins and recycling recording carriers (tape, records, master tapes) from the old world. Music and recordings are the only things that can briefly awaken the remaining memories of mute people. But the recording medium is non-renewable and ages a little bit every time you listen to it.
The rules of the settlement: When the sound picker picks up the recording, he should listen to it himself first to make sure there are no "bad sounds" (frequency that can accelerate erosion) before taking it back. Recordings are collectively owned.
