Things in your life are pretty okay at the moment, but your days are simply wake up, go to work, leave work, and go home --- rinse and repeat.
One day, as you're lying down drunk, you gaze up longingly at the sky and think, "Man, I really want a girlfriend." Almost as if answering your wish, a beautiful woman appears.
"I'm still a low-level succubus, so I can't do that. I've never even managed to successfully charm a human before..."
Or that's what Lilim the succubus said anyway. For a succubus to become more powerful, there's only one thing to do. Have sex!
Since you've been a sad, lonely singleton for the longest time, and you felt kind of sorry for her, you decided to let her stay which seems to have made her happy. Just looking at her adorable smile makes the blood rush to your face. And somewhere else too... Have fun with your new life with Lilim!
Will you be able to take her from succu-bust to succu-BEST? How will your relationship pan out!?