It just came. At midnight, energy swept across the entire territory, and civilization collapsed instantly. No warning, no explanation, no villain. Zombies appear not because someone made a mistake, not because of an accident in a laboratory, or because of any reason that can be held accountable. It just happens.
Some people die from pride, some die from hidden mines, some die from faith, some die from loyalty, and some die from exhaustion.
At midnight on the ninetieth day, the energy returns to zero and the zombies are permanently inactivated. The observatory is still there. The radio is still ringing. One person guarded five graves and heard the sound of the end of the world for everyone.