Alright, have a nother one here. Inspired in part by some other requests I read, compared with some memorable D&D games we spent in a similar setting.
What lies behind...
A woman (could be 18 but also might be interesting with an older more "set in life" woman who might be unhappily or just bored married for example) buys a full size mirror in a Carboot sale (Garage sale, Yardsale, Antiqueshop...take your pic).
Being at home with her new prized possession she begins to clean it. After having cleaned the frame she begins to clean the actual mirror. For a moment she seems to see a different person in it. This could be herself in a different outfit, a man, a Were, up to you really as well and actually just a minor detail.
Anyway ... the woman continues to clean the surface and after she is finished finds out (maybe by caressing the surface of it, her hand "dipping into it, going through it", then perhaps taking a peek through it) that the mirror is a gate into a different world.
Now I don't plan on this world as being static as in a set scenario but more of a thing such as it adapts to her emotions, to her moods. To the mood, the mindset, the remnants of a nightmare etc, she has when she steps through the mirror. It's inhabitants would be anything from fuzzy critters to Weres and monsters in the classical as well as futuristic sense. There are countless possibilities.
The reason why she would continue to go there ... well, for the younger woman it may be curiosity for the older one it might be a way to escape her usual life.
Only set factor in it would basically be the other main Character, perhaps the one she saw in the mirror in that brief reflection, he would always be there, though his appearance might change as well. He might be a Prince like hearthrob one day but a scarred and hideous Were the next. Gentle and loving one day and a Torturing monster the next. The land beyond the mirror by itself could be a peaceful meadow with a small stream running through it one day and a scene from a nightmare the next. Possibly even changing while she is there, depending on what would bring the changes on the land.
See what I mean....there are tons of possibilities with this one. And of course as always I am more than open to all suggestions, ideas, plotlines and twists as usual

And by its nature I think the RP would actually need a lot of collaboration and inspiration, more so than most others I had come up with, due to the ever changing world it is set in with its drastic changes.
If you're interested, drop me a PM
More to follow later today.