Geocentric Pivot

The sky shattered like glass. The sun turns into a deadly sting, and the air turns into corrosive acid. When the surface became a cemetery, the last engineers of mankind made a crazy choice: go down to the deepest core of the earth and build a "civilization embryo" that could breathe, grow, and survive a hundred years of loneliness. This is not a refuge, this is a bet on the dignity of human civilization - the fulcrum of the center of the earth. When one hundred thousand people ignite a glimmer of light in the abyss, can the most inconspicuous life change the fate of an entire race?