Last week, the impossible happened when Barbie, Pauline, and company re-entered the Dome. No one is more shocked to see Pauline then her old husband, Big Jim. His eyes basically fall out of his sockets when he sees her. At first, he thinks it’s just another Dome vision (ie Dodie). She tries to convince him, but he is still in disbelief as she reveals her death, the car crash, and everything was faked because she thought she could protect them by taking the Dome with her. Big Jim is super upset, saying she destroyed Junior and he thought it was all his fault.

Meanwhile, local science teacher Rebecca makes the astute observation that the Dome has accelerated the seasons because it is getting super cold in the Dome and some of the trees’ leaves are turning red. Autumn in the Dome! This scientific discovery is interrupted by the dramatic return of Barbie. Julia runs down the street into his arms as the music swells.

Norrie and Joe are experiencing the effects of the sudden coldness, so they decide to cuddle on the couch and make out. Unfortunately for Joe, Norrie is concerned about Melanie being gone for a day. She gets up and discovers the egg is missing. D’oh! They had to find Melanie now.

Well, Melanie just woke up from her nap in the bunker with Junior. She says she has to go find Julia, making a joke about being locked up in the bunker by Junior. #toosoon. She kisses him goodbye and leaves. Dead Angie (Britt Robertson) suddenly appears to Junior telling him not to follow his heart. Her head starts to bleed. Melanie comes back, thinking Junior was talking to her and the vision of Angie disappears.

Barbie explains to Julia and Rebecca how he got out of the Dome and then got back in the Dome. He explains he had a vision/memory upon reentry, that Lyle is missing, and they need a plan to get everyone out of the Dome via the cliff. He says they need to take the egg. Julia doesn’t agree.

Sam runs into Melanie and tells her that it was Lyle, not him, who killed her those years ago. He apologizes, atoning for his sins of trying to cover it up. Melanie says if they had just trusted her before, then none of this would have happened.

As Jim looks at all of Pauline’s childlike paintings, he demands answers from her. She explains how she and everyone else got in the Dome, mentioning that Lyle didn’t make it. She says she came back for Junior and Big Jim and is sorry for running. Big Jim says she was right about everything that happened and admits he wasn’t a good man in the past, but says the Dome has changed him. Ya know, the same spiel he always gives. He wants to be a family again, once he leads the town out of the Dome.

Barbie and Julia argue about if they should leave. Julia thinks the Dome is protecting them. Barbie says they need to leave and they can use the egg as leverage. Julia will jump first to make sure everyone in town gets out. Mel arrives and hugs Barbie. Julia casually asks where the egg is, but Melanie refuses to them them.

As Joe and Norrie search for Melanie at the school, they run into hacker Hunter. He explains who he is and tells Joe and Norrie they are famous outside the Dome. He shows the his Hounds of Diana page and wants to help them build a radar/electro tracker thing to find the egg.

Melanie and Barbie have a private conversation on the porch. It is then we discover that Barbie and Melanie are half-siblings. LA-DI-DA. Apparently Barbie’s father had a former wife named Laura, who is Melanie’s mom. Barbie remembered Melanie in his vision. What a coincidence it all is. Barbie says it all makes sense (no, it doesn’t!) and they have to lead the town out of the Dome with the egg. Melanie still refuses, sensing something bad will happen if they do.

Big Jim and Pauline look at pictures of baby Junior, leading Pauline to cry about missing his life. Cue Junior’s entrance. She laughs, they hug, it looks all good. She explains it’s a long story (ya don’t say). Big Jim leaves to form an exit strategy. Once gone, Junior and Pauline chat about her secret video and Pauline says she isn’t good with his father. Junior is super pissed about Sam killing Angie because of Pauline’s predictions. He rushes out. Suddenly, the egg glows and starts making a screeching, irritating noise that causes Pauline to freak out.

At the Briar Rose Cafe, Julia and Barbie try to convince Andrea and Farmer Tom to go along with their ‘exit the Dome via the cliff’ plan. Andrea wants to wait until Big Jim says something. Rebecca explains we have to get out because of the cold and dwindling resources. Farmer Tom says he is in! Yay, farmer Tom.

At the police station, Hunter reveals he is a major geek/hacker to Norrie and Joe. His device is complete but Joe says he can’t come with them to find the egg. Hunter is okay with it. As Joe and Norrie discuss everything, drunkard Phil, who is in jail, overhears.

Big Jim arrives to negotiate with Barbie and Julia. He wants to jump first. After some talking, Barbie agrees, knowing his family is in the Dome and Big Jim wouldn’t risk losing them. So, is Melanie on board? She sort of it. She wants to carry the egg and go along with Barbie last. Barbie promises her that their dad won’t care about the egg. He’ll just be glad to see her alive again. Julia doesn’t think Barbie should make promises he can’t keep. She starts talking about their “post-Dome” life and he tells her he wants her in his life (no mention of her former dead husband, who Barbie killed in Season 1).

Big Jim arrives back at home to tell Pauline he is gonna get her and Junior out. Pauline, however, is in a craze, painting a picture, screaming about the egg and wanting it to stop. Big Jim doesn’t understand and he locks her in her painting room. Once outside, he hears the egg screeching. He goes to the bunker and tries to grab the egg, but it blasts him backwards across the room.

Norrie and Joe rush into the bunker. Norrie is able to pick it up with no effects. Big Jim suddenly rises and pulls a gun on Joe, saying they are going to take it to the tunnel and throw it off the cliff. Big Jim says he has no problem killing Joe, so they go along with him.

Meanwhile, the other Rennie, Junior, bursts in Sam’s cabin with his gun blazing. Sam tries to explain why he did it and apologize but Junior is not forgiving. He starts beating Sam violently and wants Sam to fight back. He grabs an ax and is about to kill Sam when a vision of Angie appears telling him to stop. She says Junior can’t kill him because he still has a part to play. Junior says he loved Angie. Angie disputes that, saying Junior never loved her, he just wanted to possess her. Junior just thinks she is the Dome, playing a trick on him. Junior grabs the ax and swings, missing Sam’s head by inches. Junior tells Angie that he really did love her, but she is gone.

Big Jim leads Norrie and Joe through the school and into the tunnel. Hunter spies them from one of the classrooms. The egg starts freaking out and glowing as they get close to the cliff. Norrie refuses to throw it, so Big Jim takes it and throws it over the cliff. EARTHQUAKE!

The ground rattles. Pauline stands still in her room. Hunter hides, trying to get a signal. Melanie faints. Phil escapes his jail cell. Julia and Barbie bring Melanie to Sam’s cabin and he revives her, leading Junior to believe Angie’s claim about not killing Sam. Junior tells everyone he doesn’t have the egg as Melanie awakens.

Big Jim rushes out of the tunnel, leaving Joe and Norrie to fend for themselves. Luckily, Hunter helps them out of the tunnel. Another earthquake rattles the town. Big Jim finds his wife and tells her he threw the egg over the cliff and now they can go, but Pauline disagrees. She says her visions are gone and cries, repeating, “What have you done?” to Big Jim. Stupid, stupid Big Jim.

Barbie and Julia arrive at the school and reunite with Joe, Norrie, and Hunter. They explain what happened with Big Jim and the egg. Suddenly, Phil bursts into the school and rushes down the tunnel, jumping over the cliff. Barbie and Julia follow and see that the cliff now has a bottom full of nasty looking upward spikes, one of which has an impaled Phil atop it. THERE IS NO EXIT FROM THE DOME NOW. They are stuck. Oh NO!!!

What did you guys think of this week’s episode? Let me know in the comments below. Only three more left! I’m glad the escape route is gone, but what are they going to do now? Tune in next week to see.

Under the Dome airs Mondays @ 10/9c on CBS. Watch full episodes online at CBS.com, Hulu and Amazon Instant Video.