When the Sky was Blue -The Last Sky-

Humanity didn't end in a single day. It burned slowly. Wars consumed nations. The atmosphere became poisonous. Cities disappeared beneath smoke, and those wealthy enough to escape retreated underground, leaving millions behind. One father refuses to accept that his daughter is going to die simply because she was born on the wrong side of the world. So he goes to the surface. He never comes back. Centuries later, Earth is green again. The machines that inherited the planet have rebuilt its cities, restored its atmosphere, and begun to wonder what became of the species that created them. Then they find something that should not exist. Human life. And suddenly, the machines are faced with a question they were never programmed to answer: Should humanity be brought back?