Inside the mini-dome, a monarch butterfly starts to emerge. Joe, Ben, Carolyn, Norrie, and Linda watch and Linda tells them to move away. She demands to know how long that they've known, and Carolyn tells her that the kids think the egg generates the Dome. They tell her about how the monarch is to be crowned and Joe says that they need to get the butterfly out of the mini-dome before it is hurt.
Big Jim hauls Barbie back inside city hall and punches him, insisting that he told the truth about Barbie killing the others. He then tells Barbie that he'll get his justice.
Junior leans against the dome and yells at it to explain why it wants his father dead.
In the clinic storage room, Julia insists on going out and clearing Barbie's name. Angie points out that Big Jim will have her killed, but Julia insists on doing it or dying.
Linda declares the mini-dome as police property, but Norrie interrupts her to point out black spots are growing on the surface of the mini-dome.
Big Jim puts Barbie back in a cell, and Barbie says that he plans to take him down with him. The councilman says that he can end it with one bullet, but Barbie figures that he won't because there's no audience.
Every time the butterfly touches the dome, it leaves a black spot. It finally collapses and Ben realizes that the light is going out outside.
At the jail, Barbie and Big Jim notice the sunlight going away. As the townspeople start to panic, Big Jim runs outside and sees black spots covering the surface of the dome. The emergency lights come on as the sunlight goes away.
At the dome, Junior sees the dome's surface turn solid black and wonders what it's trying to tell him.
At Ben's house, Joe figures that the dome is telling them to get the butterfly out of there before it dies. Ignoring Carolyn, Linda calls in all available units. Junior picks up and she tells him to get there, and Big Jim hears as well. As he drives over, the dome starts screeching again. Joe reminds them how they stopped it the last time and they prepare to touch it. Linda insists on touching it herself since it's police property and reluctantly reaches forward. The mini-dome blasts her back against the wall.
Angie and Julia hear Linda on the stolen police radio but Julia insists on going to find Barbie before it's too late.
As Carolyn confirms that Linda is okay, Junior arrives and demands to know what's going on. He doesn't want to find Angie, pointing out that she ran out on him to save Barbie. Ben reports that Big Jim has pulled up and Joe and Norrie ask Junior to help them before his father gets the mini-dome. After a moment, he agrees to help.
Angie helps Julia get to the police station and the editor finds Barbie in his cell. He wonders how she can be moving and Julia figures that something wants her moving. They kiss as Angie arrives with the keys and lets Barbie out.
Big Jim runs into Ben's house and finds Linda unconscious on the floor. The others have escaped with the mini-dome and she explains that the kids think the egg is the way to shut down the dome.
Junior drives away with the others and tells them that he knows Angie stole a police radio.
Phil and another volunteer come into the police station just as Barbie, Julia, and Angie come running up. Barbie manages to take Phil down despite being handcuffed, but Phil grabs Barbie's dogtags. When the other man goes for his gun, Angie knocks him out with a fire extinguisher. Julia picks up Barbie's dogtags while Joe gets on the radio and publicly broadcasts to Angie, telling her to meet them where they used to hide when they broke their mother's mirror.
Joe has Junior drive them to the cement factory. Angie, Barbie, and Julia arrive and Julia insists convinces Junior that Maxine shot her, not Barbie. The dome glows with red handprints on the surface.
As Big Jim starts organizing the search for Barbie, Phil calls to tell him and Linda that Barbie escaped.
The four kids touch the mini-dome in the designated spots. It glows brightly and then the forcefield disappears, leaving the egg sitting in a pile of dirt. Angie spots the butterfly lying in the dirt. Norrie touches it and it flies over to Barbie. Joe says that Barbie must be the monarch.
As Big Jim drives around, he sees townspeople gathering at the church. He pulls over and Andrea tells him that everyone is getting right with God because they believe that the Apocalypse is upon them. She goes in to join the others, and Big Jim steps up and tells the congregation that God hasn't forgotten about Chester's Mill. They object, pointing out that now the sun is gone, and Big Jim promises that nothing will happen to them. When they wonder how he can promise that, Big Jim admits that he can't. But he insists that he has faith in all of them and faith that God would never ask more of them then they can handle. Big Jim takes a Bible from Andrea and says that things are going to change, and promises that Chester's Mill will have a new dawn.
Junior refuses to accept that Barbie is the monarch. The egg starts to twitch and glow, and the cement factory shakes. Everybody starts to run except Julia, who reaches forward and picks up the egg. It stops moving and everything calms down, and the butterfly lands on the egg. Barbie steps forward and says that Julia is the monarch.
Big Jim goes to his office and calls Phil in. He tells him to find as many carpenters as he can and shows him pictures of a gallows. Phil wonders if he's serious and Big Jim says that they need to show people that there's law and order, and that they need to do it for Dodee.
Linda goes to the McAlister barn and sees the constellations that they traced on the walls. She calls into Big Jim, saying that there's no one there, and finds writing about "The pink stars are falling in lines" on the wall. When she reads it to Big Jim, he remembers his wife's painting with Junior and tells Linda to meet him at his house.
At the cement factory, Norrie wonders what they're going to do next. Julia has no idea and Junior says that proves that there's no such monarch. He wants to take the egg to his father, but Barbie says that he watched Big Jim shoot Maxine dead. Junior refuses to accept that and insists that Big Jim is the only thing keeping things together. He reminds Julia that she told him about how she was fired from her job in Chicago because she lied, and orders her at gunpoint to hand the egg over. Julia tosses it to Angie and tells her to run, and she runs out with Joe and Norrie. Barbie, still handcuffed, jumps Junior and tells Julia to run. Junior easily subdues him and hauls him away after Julia escapes.
Big Jim takes Linda to Pauline's workshop and shows her the painting showing a black egg against a sky of falling pink stars. He explains that before she died, Pauline kept talking about pink stars.
Julia joins the others in the woods and tells them what happened to Barbie. Norrie suggests that they ask the egg what to do, and Julia hands it to her. After a moment, Norrie asks it to tell them what to do. Noting happens at first, but then an image of Alice appears to them.
Big Jim and Linda wonder how Pauline could have known what would happen. He blames himself for not realizing there was something else to his wife's illness, and Linda tells him that his family must be important. Junior calls in and says that he's bringing Barbie in.
Norrie starts to go to Alice, but Julia holds her back, saying it isn't her mother. Alice steps forward and says that "they" are still learning how to speak with them. They have taken on a familiar appearance to cross the divide, and Joe figures that it's whoever sent the dome to Chester's Mill. Angie asks why they're punishing them, and Alice says that the dome was sent to protect them. Julia asks from what and Alice says that they'll see in time. It tells them that they must earn the light by protecting the egg, and Julia realizes that if they fail then it's the end for everyone. She asks how they protect it and from who, but the image of Alice disappears.
Junior drives Barbie to the police station, ignoring Barbie's warning that he's on the wrong side of things. Once he's in a cell, Big Jim welcomes him back as the carpenters build the gallows outside. Big Jim asks where they took the egg, figuring that it's the key to controlling the dome. Barbie refuses to answer and tells him that he's no god.
Julia and the others go to the diner and try to work out what to do. Big Jim calls over the radio, telling Julia to bring them the egg in return for a reduced sentence for Barbie. Junior goes to his father's office and tells him that they want to assassinate Jim for murdering people. Big Jim asks if he believes it, and Junior wonders if he should. His father says that he went to see Pauline's studio and figures that the paintings represent their destiny. Pauline used to say that a good man will do anything for the people and admits that he's taken lives. However, Big Jim insists that they needed to be taken for the good of the town. He didn't tell Junior because he wanted to protect him, but now he realizes that the two of them were chosen and Pauline knew it. Big Jim says that they need to make the hard decisions and lead, and promises that there will be no more secrets. He offers Junior his hand and after a moment, Junior steps forward and hugs him.
At the diner, Joe wants to save Barbie but Norrie and Julia figure that the egg can't fall into Big Jim's hands. Julia says that it's her decision and tells the three kids to go somewhere safe.
The townspeople gather around the gallows while inside city hall, Big Jim and Junior wait until Julia's hour is up. Big Jim nods to Junior, who goes to bring Barbie out.
Julia drives to the lake and gets out, holding the egg.
Big Jim goes out on the gallows and tells the townspeople that outsiders have been trying to divide them. Junior brings Barbie up to the noose as Big Jim sentences him to death.
Julia goes out on a boat and looks at the lake waters.
Junior puts the noose on Barbie's neck.
Julia takes out Barbie's dogtags and studies them carefully.
Junior prepares to pull the lever.
Julia drops the egg into the water. A red light glows from beneath the surface and hundreds of pink lines shoot up into the air from it.
In town, everyone sees the lights and Big Jim announces that it's a blessing from God in favor of what they're doing.
Joe, Angie, and Norrie go out and look at the sky.
The stars all form into one glowing point of light. The blackness disappears, revealing a bright white surface. Junior asks what is happening, and Big Jim tells him to pull the lever. After a moment, Junior starts to pull the lever.