A small town is suddenly and inexplicably sealed off from the rest of the world by an enormous transparent dome. While military forces, the government and the media positioned outside of this surrounding barrier attempt to break it down, a small group of people inside attempt to figure out what the dome is, where it came from, and when (and if) it will go away.

An invisible and mysterious force field descends upon the small town of Chester's Mill, Maine, USA, trapping residents inside, cut off from the rest of civilization. The trapped townspeople must discover the secrets and purpose of the "dome" or "sphere" and its origins, while coming to learn more than they ever knew about each other and animals too.