In 2100, the earth became uninhabitable. The human race was at the edge of extinction until one day when “the Successor” created an angel AI: Eden’s Echoes. Capable of physical manifestation and cellular control of all living beings, those who possess such AI were able to mutate and adapt to the earth's surface's unforgiving conditions. But suddenly, as if the heaven’s gates closed, the Successor disappeared and no new Echoes were created. An endless battle for one’s right to live begins...