Pretty Moppet is a young woman who was raised by Spike and Drusilla.

Her real name is Jene Violetta Visser but Drusilla changed it to Regan (which means, quite fittingly, 'Little Queen').
They kidnapped her from her parents when she was only a toddler because Dru believed that she was something 'very special' and Spike (of course) couldn't refuse her.

It ends up that Regan IS special. According to everything that Spike has read, she is the (supposedly) very powerful heir apparent to a breed of creatures that will (according to prophecy) one day bring all that is darkness out of the shadows and into power. They are not human and they are not demons. Angel used to call them 'the things above us'. Regan is supposed to be the one who will bring about this whole coup d'etat of the undead with all of her magnificent powers.
Unfortunately, up until now her powers haven't surfaced yet. Which is a bit of a bad thing for someone who would be the grandest trophy any demon could ever snag.

Being raised by Spike and Drusilla, Regan lives in a weird reality (I mean, can you imagine?) where love, ador and 'family values' co-exist quite nicely with bloody carnage and insanity. She lived quite happily in this world that they have created for her, having tea parties with Drusilla and hunting for Slayer's with Spike. She is a ruthless killer just like both of her 'parents' but is also a very sweet and even sheltered girl.

As Regan inches toward her 25th birthday, Dru, Spike and the rest of the underworld hold their breath . . . waiting for something to trigger her powers so she can finally bring about 'Hell on Earth'.

The only question is:  Will Regan want to bring about this new world? And if not . . . then what?!?