The Red Door

 is the ninth episode of the second season of Under the Dome.

Synopsis
After being captured at the edge of the Dome, Barbie is taken into custody for interrogation by a private security firm. It is then revealed the firm has been hired by Don Barbara to work with his energy company in order to obtain the egg at any cost, even at the expense of Barbie. Don forces his assistant Hunter to send a recorded message to Julia in which Don claims to care about Barbie, telling Julia that handing over the egg will be the only way that his son will be released. If not, he doesn't know what kind of harm could befall him. To the surprise of Melanie, who is opposed to giving into the security firm's demands, Julia appears to be willing to exchange the egg for Barbie. Barbie eventually manages to knock out his interrogator and uncuffs himself, and heads to the Hounds of Diana headquarters, where he meets up with Hunter, Hunter's co-worker, Lyle, Sam, and Pauline. Pauline reveals that Hunter was one of her best students when she taught art. Barbie, shocked to see Sam alive, reveals to everyone that Sam murdered Angie. Pauline is horrified but calms down somewhat when Sam tells her his rationale behind his actions, and that he hasn't laid a hand on Junior. Pauline feels partially at fault in that her paintings led Sam to do what he did, and she realizes they must go back to Chester's Mill to atone for their sins. Meanwhile, back in Chester's Mill, Junior reveals to his father that he knew that Barbie was still alive, and that Barbie's captors desire the egg. Big Jim then heads to the Dome barrier, where he exchanges written messages with a guard in charge, who agrees that if Big Jim can get the egg, he and Junior will be allowed to escape the Dome. However, Junior and Melanie take the egg back to Junior's storm shelter, and Junior reluctantly agrees to lie down with Melanie. Back in Zenith, Barbie realizes that the red door that may lead back to Chester's Mill is the door to a root cellar in his backyard, repainted when he was a kid. The group uses Hunter's co-worker as a diversion and successfully enter the cellar in Don Barbara's backyard without getting caught. They discover a tunnel that Barbie can't remember seeing before, and once inside, each individual is engulfed by a spiraling swirl of mist that Pauline had predicted earlier. Sam flashes back to after Pauline's "death," when he had to tell a disappointed young Junior that he had to stay with his father instead of coming to live with his Uncle Sam. Barbie flashes back to when the root cellar was first built, when none other than Melanie was sent by her "mom" and encourages him to leave his handprint on the fresh paint. Pauline flashes back to the pit where her and her friends first discovered the Dome. Melanie is there and says, " This is where it began, and this is where it ends. For all of us." The group awakens from their flashbacks to find themselves in the lake back in Chester's Mill--all except Lyle, who is nowhere to be found. They swim to shore and go their separate ways, each of them having their own business to take care of. Pauline goes back to her old house, and is looking at old photos when she turns around to see her mystified husband at the foot of the stairs.