Haiiro no Sora ni Ochita Tsubasa

Humans and angels.... They first met long time ago. Angels told humans some of the world's secrets and humans learned alchemy. Humans gradually forgot who they were due to their curiosity and tried to find a secret of angels, their agelessness. Though humans soon found out that it was impossible for them to be ageless, some silly humans kept on hunting angels and doing research. However, God got angry and used his power which prevented humans from getting more knowledge. Some angels were contaminated because of his power, but God had to do that to warn humans. Angels who didn't bring knowledge.... They were regarded as useless, but a nobleman took advantage of their beauty. Their beautiful and ageless bodies.... It was a treasure for humans, but there was something dangerous.... "Netsiv Melah" When angels went back to heaven, they caused Netsiv Melah. After a storm stopped, everything around it turned into salt.... Angels usually tried not to involve anything, but.... Netsiv Melah often happened because of angels who were contaminated and destroyed by some reckless humans. Humans, however, kept on spending money, doing research, and finally invented.... A demeanor to blacken their white wings and hearts by pleasure and desire called Desperation.... It couldn't cause Netsiv Melah, either. Desperate angels, who gave pleasure to humans, became valuable as sex slaves....