The final episode of "Under the Dome" Season 3 is titled "Go Now." The dome is shutting down and there is a danger that it may become the killer dome. Only an escape route can save the residents of Chester's Mill. The crater that appeared after Melanie was sucked into a hole has become that exit route. But, according to the preview, "not everyone will get out alive."

The preview also indicates that the death of Pauline will turn Big Jim into a violent, murderous man who just wants his wife to come back to life. He vows to murder if the dome does not resurrect the dead Pauline. He can be seen hitting Sam in the preview clip.

A lot happened in the penultimate episode of "Under the Dome" Season 2, "Turn." The dome continued to contract inwards. Barbie convinced his dad to return the egg, showing him the proof that Melanie is alive. But, Don Barbara's security man stopped him from handing the egg to Barbie, as they both take orders from someone else. Melanie's condition continued to deteriorate and she was close to death. Big Jim encouraged Pauline to paint again to help Melanie and the people inside the dome. She painted the eights hands. Melanie was brought to the location, the middle of the dome, where the egg was originally found, and as Angie was dead, Melanie's both hands were used to make it eight hands, four new and four old hands of the dome.

Melanie woke up but soon a hole swallowed her and she disappeared. Lyle stabbed Pauline with a knife, as he wanted her and him to be together in the end. Pauline was dying, while Big Jim killed Lyle.

According to the official synopsis of the final episode of "Under the Dome" Season 2, "A potential exit from the Dome will get revealed just as the walls begin closing in on those trapped in Chester's Mill."

Speaking about how the tunnel to Zenith will play into the final episode, Rachelle Lefevre said to TV Line, it will be involved massively," adding, "There is evidence of the possibility of escape. Obviously, Barbie left. And came back. So there is evidence that it is possible. If you know you can get out, you're going to try."

Caitlin Parrish and Cathryn Humphris have written the final episode. It has been directed by executive producer, Jack Bender.

There are reports that "Under the Dome" is likely to end on a cliffhanger. It indicates the possibility of Season 3. However, CBS has yet to announce that it has renewed its summer series for another season.

In her interview with TV Line, Lefevre said that she has theories about what the audience may learn in Season 3. She added: "I don't want to give you any of them because I'm afraid to be right. I don't want to accidentally be spot-on and then I gave it away."

[Youtube/Under the Dome]