Every night, an art academy student encounters the mysterious Lilith — a succubus who comes to him through a portal and secretly feeds on his life energy. Gradually, Lilith becomes his muse. But the more attached she becomes to him, the harder it is for her to feed on his energy, knowing that one day it could destroy him. Meanwhile, Sentir, an elder demoness, is watching Lilith and considers her behavior a violation of the rules. Sentir threatens to strip Lilith of her demonic powers if she refuses to fulfill her purpose. Now Lilith must decide whether to continue feeding on the man for whom she has become an inspiration and a muse, or defy the laws of the demonic world. And all the while, Sentir is preparing her next move.