A young man attempts to prevent the suicide of his sister's friend but ends up dying with her. He wakes up completely alone and lost in a dark forest, in a new world full of beast people and worst--or best?--of all, in the body of the girl he tried to save.

Earth has been invaded and occupied by an alien species known as the 'niao.' Millions of humans have been forced off Earth to be used as disposable labor for the niao empire. A secret army of humans, led by the mysterious Lindwyrm, is preparing to fight back but will their violent methods free hu...