As the Dome collapses, Joe, Norrie, and Hunter find a way out. Meanwhile, Big Jim loses someone close to him and tries to make a deal with the Dome.
With the egg gone, the Dome starts contracting, threatening everyone within. Barbie contacts his father and demands the egg, revealing the presence of his half-sister. Meanwhile, Melanie's condition grows worse and Big Jim works with Pauline to create a new painting that will show them the way.moreless
The temperatures inside the Dome plummet and Julia and Barbie go to save the food, while Big Jim looks for fuel to power the generator at the high school. Meanwhile, Melanie begins to suffer and Junior realizes that her health is tied to the egg.moreless
Big Jim is reunited with the wife that he believes is dead, while Barbie and Julia are reunited and realize that the egg is missing. Meanwhile, Joe and Norrie meet Hunter and set out to find the egg, as the temperature beneath the Dome begins to drop.moreless
The mercenaries capture Barbie and demand that he get the egg for them. Meanwhile, Sam, Pauline, and Lyle try to track down the red door from Pauline's visions, and Big Jim makes a deal with the mercenaries guarding the Dome.moreless
Barbie makes contact with a mysterious hacker who knows that Barbie's father Don is playing a dangerous game. Meanwhile, new sheriff Big Jim suspects that someone is after him and enlists Junior and Rebecca to help him.moreless
When Barbie tries to recover Sam's body, he is pulled into the chasm and finds himself outside the Dome. He sets out to find the one man who can help him get back into the Dome with Julia: his father, Don. Meanwhile, Julia tries to conceal that Barbie is apparently dead but Big Jim finds out and uses the information for his own purposes.moreless
Acid rain threatens the residents of Chester's Mill, further endangering their lives. Meanwhile, Rebecca and Lyle argue over the reason for the Dome's existence.
Before Big Jim can execute Barbie in the town square, an electromagnetic pulse fells many of the townspeople. Meanwhile, Julia rescues a woman who falls into the lake out of nowhere, and Big Jim receives two visitors who try to convince him to see the error of his ways.moreless
The CSI team investigates when a man is found dead inside a human-sized hamster ball.