Adventure Idea...

I had this idea a few days ago of a scene where the Players plunge the city of Avonleigh in to the Shadowfell in order to save it from an invading attack.

I pictured the general of the invading army arriving at the suddenly vanished town to find a small glowing sphere hovering a few feet above the ground at the center of where the town used to be. The general would reach out to grab the glowing sphere.

In the Shadowfell the characters would see a shadowy image of the general as though he just walked through a building. They would see him grab the glowing sphere and move it, but in the shadowfell a dark glowing sphere would be left in its place that the characters would be able to move and take with them.

If I use this idea I would have to come up with the pieces of how the characters would get Avonleigh transported to the Shadowell and then come up with and adventure and some pieces of how they would get Avonleigh back to the Natural World.