Japanese anime set in the near future following an apocalyptic disaster. There are only 20,000 humans left in the world and they are all women, due to the warring nature of men. Many of these survivors believe their fate is sealed and that there is no way to prevent mankind becoming extinct. Others, however, are devoting there lives to biological engineering, in an effort to make the human race live on. Their conflicting ideologies result in the women dividing into two opposing sides.