Yoru Momiji, a guy who feels extremely desperate with his life, past and future, and wants to end everything of his own.
In front of him, who couldn't find the slightest fun in his life, a succubus named Lilith suddenly appeared, aiming at hunting spirit.
However, as a special energy that humans only release when they are in a happy mood, Lilith cannot collect the essence from Yoru Momiji at all.
Faced with such a situation, Lilith, who felt that her dignity as a succubus was provoked, decisively challenged him to obtain the highest quality essence from him.