Mirage ~In'en no Shokushu Byoutou~ Another Story Of D'erlanger

This is another story of "D'erlanger". Yui is hospitalized for a sudden illness at Seihou Hospital. One night, when she wakes up, she finds herself in a nightmare world "Mirage". She walks around the hospital and encounters mysterious monsters.... Somehow, she is saved by men who fight against monsters with special ability. A man tells her that endless battles between humans and monsters are taken place in "Mirage" and she is forced to be a sex slave for those men who fight against monsters because she has no special ability to protect herself. One night, here comes a new woman, Kikukawa. She tries to destroy the relationships among men and they start to fight against one another. All the men are annihilated and Kikukawa is also gone somewhere....