[1] The incubus Sebastian is the bastard child of a succubus and the wizard Koltak.

Forced to flee every city or town he settled in, he has never known a home.

Until one day, his cousin, 15-year-old Glorianna Belladonna, creates a landscape where demons can live, called the 'Den of Iniquity'.

Meanwhile, Sebastian, living in the Den of Iniquity and ignorant of the sacrifices his cousin has made for him, begins to tire of the life he lives, finding simply having sex with women no longer interesting.

She is a catalyst whose "heart wish" (a strong wish deeply embedded within her) delivered her to the Den.