By chance, the exorcist Xiaoyu was forced into a living arrangement with Heiyao, the succubus who killed her foster-father. But Heiyao seemed to have lost her memories!? Xiaoyu didn't trust Heiyao, so she decided to stay and keep an eye on her. Heiyao didn't mind, as she tried to tease and seduce Xiaoyu in order to feed her hunger… They might fight all the time, but they both know there are other dangers lurking, with whoever was behind Xiaoyu's father's murder, whoever sealed away Heiyao's memories, and something else…