Taking Myrleena's cue, here is my spin on one possibility. A work in progress, as most things are but wanted to put down what I've come up with. I don't have a strong preference of which character I might play. Please do feel free to add to this or suggest an alternative.Grimoire of Lamiae
Setting: Kingdom of Gwynedd (5th Century) amid the forested hills and mountains. Secret sects and whole villages are home to pagan worshipers and covens of witches competing for the religious hearts and minds of the populace. This would be post Roman, pre-Christianity era steeped in superstition.
Plot: Meroe and a handful of her close associates, fellow witches, break from the larger coven to form their own. Meroe had previously traveled to Macedonia on a witches pilgrimage. Returning home, to the Kingdom of Gwynedd, Meroe brings with her an ancient Greek text called the Grimoire of Lamiae. In an attempt to secure their ligitmacy, power and standing with the large Mother Coven, the group decides to execute a commune laid out in the book to commune with Lamia, the author of the grimoire. In their ignorance and inexperience however, they unwittingly summon Lamia herself, now a deviant Succubus.
At first, the conjuration of Lamia seems to be a powerful if unexpected occurrence. The small group of witches revel in their success, believing the succubus is under their control. Lamia however has other plans. She will use the witches to attack the Mother Coven, jealous of their power and standing. One or more of the smaller group of witches may be transformed into a lesser succubus.
Matters will get out of hand and the witches will lose control of Lamia. Humbled and in great danger the group will with the help of the Mother Coven attempt to banish Lamia back to the Abyss.
I used the following as inspiration from which I borrowed ideas from, although only roughly.http://en.wikipedia.org/wiki/Lamia_(mythology)http://en.wikipedia.org/wiki/Kingdom_of_Gwyneddhttp://en.wikipedia.org/wiki/European_witchcraft