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
Barbie and Sam investigate the tunnel behind Melanie's locker at the school, but an explosion cuts them off from the others. A dust storm comes up and Julia must choose whether to help the town or try and rescue Barbie. Meanwhile, Joe and the other three hands recover the egg from the lake.moreless
Julia takes over as the new leader of Chester's Mill, after the town becomes divided over Big Jim and Rebecca's population-control plan. Meanwhile, Joe and Norrie help Melanie search for clues about her identity at the dome wall.moreless
Barbie and Julia take opposing sides when Big Jim and Rebecca take extreme steps to extend the town's resources. Meanwhile, the mystery of Melanie Cross deepens.
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.
Barbie risks his life to help Rebecca save the Chester's Mill food supply when she discovers an infestation of butterfly eggs on the town's crops.
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
As Big Jim continues to secure his power and takes steps to eliminate Barbie, the Monarch is crowned and the Dome sends a familiar face to Joe and Norrie to reveal the secret of the Dome.moreless
While Big Jim convinces the townspeople to hunt Barbie down for his alleged crimes, Joe and Norrie move the mini-Dome
Big Jim frames Barbie for the deaths of his enemies, while Junior abandons the group and they discover the consequences when a storm gathers.
Julie learns about Peter's past, while Junior gets a promotion. Meanwhile, Maxine forces Barbie to fight in a staged arena contest.
Big Jim receives an unexpected visitor from his past, one with connections to another person trapped beneath the Dome. Meanwhile, Joe and Norrie find the source of the Dome in Joe's barn, and Barbie and Linda encounter someone with a connection Chester Mill's drug dealer.moreless
Ollie takes control of the town's water supply and Big Jim must join forces with Barbie and Linda to get it back before his own control of Chester's Mill is threatened.
While Harriet goes into labor, Joe and Norrie investigate the source of the Dome in an attempt to save themselves and their fellow townspeople.
When the townspeople realize that their food and water are running out, they begin looting Chester's Mill for whatever remaining supplies that they can find.
Barbie receives word from the outside that the government is drawing their men back as the Dome interferes with magnetic fields.
When Chester's Mill is stricken by a meningitis outbreak, the townspeople panic when the clinic runs out of medicine and the Dome prevents anyone from bringing in new vaccine. Meanwhile, Julia learns the secret that Peter was hiding from her, and Junior is left in charge.moreless
Joe ends up holding a party at his home where the town's teenagers gather to enjoy one of the few generators in town after the power goes out. Meanwhile, Barbie and Big Jim search for Paul after he escapes custody, and Junior looks for a way out of Chester's Mill.moreless
As the reality of their situation settles in, the townspeople's tempers start to fray. Meanwhile, Big Jim sends Reverend Coggins to remove the evidence from Duke's house, and Junior stalks Barbie.