Barbie's (Mike Vogel) been captured, and he's inside an interrogation room where a less-than-friendly officer asks him why he was at the Dome. Naturally, Barbie isn't talking. The interrogator threatens him; he'll cooperate, and get Julia (Rachelle Lefevre) to turn over the "power source" (the egg) ... or else. Meanwhile, Big Jim (Dean Norris) questions Julia, who still doesn't tell him Barbie's alive. Norrie (Mackenzie Lintz), Joe (Colin Ford), Melanie (Grace Victoria Cox), and Junior (Alexander Koch) worry that Big Jim is onto them. Joe wonders if the guys who took Barbie are the ones who want the egg -- so while Junior goes to keep an eye on his father, the others head to school to see if another email comes through. Junior's plans go awry when Big Jim forces him to admit the truth. In Zenith, Pauline (Sherry Stringfield), Lyle (Dwight Yoakam), and Sam (Eddie Cahill) decide to check the playground for the red door from her painting. Barbie's father Don (Brett Cullen) tries to convince his son that the egg is their best bet for his release -- however, we find out that the "black ops" team that took Barbie is part of Don's own security firm! Dear ol' Dad wants the egg for himself!
The only red door Pauline sees at the playground is a bust; meanwhile, people appear to be tailing the trio, so Lyle and Sam scatter to throw them off. The kids and Julia wait at the school -- and their patience is rewarded; Hunter (Max Ehrich) sends an email on Don's behalf, a video in which Don asks Julia (almost too nicely) to turn over the egg in exchange for Barbie's release. Strangely, Melanie recognizes Don's voice. Over in Zenith, Barbie manages to overpower the interrogator and escape!
Big Jim finds Rebecca (Karla Crome) at the Sweet Briar Rose; surely, Julia told her that Barbie is alive. No -- Rebecca is genuinely surprised. Big Jim wonders if the egg really does power the Dome as some believe, and asks Rebecca to locate it. Instead, she finds Julia and the kids and spills about Big Jim's plans. Julia strongly considers turning over the egg, and Joe and Norrie agree -- but Melanie is worried. In Zenith, Pauline is drawing a spiral in the ground; seeing shapes is how her visions start, but this particular spiral scares her. The trio now needs a safe place to hide, and Pauline knows just the spot; it's the "Hounds of Diana" safehouse, manned by Hunter (Pauline's former student) and another hacker named Trevor. Someone else shows up at their door; it's Barbie! And he can't believe what he sees...
Big Jim's gone to the Dome's edge, and asks to speak to the person in charge. He explains that he can get them what they want -- the egg -- but they must deal with him alone. The guard leader agrees ... but Big Jim can't bring the entire town with him as well, only his son. The leader pulls up the egg's GPS location; it's at Angie's apartment. At the safehouse, Pauline confronts Sam; did he really kill Angie like Barbie said? While Hunter searches online for all the red doors in Zenith, Barbie realizes the door in Pauline's picture is actually at his father's house. Junior grabs the egg before his dad does, and he and Melanie decide to work together to keep it safe; Junior believes the best place for it is right under his dad's nose, in the underground bunker. Meanwhile, Barbie sends Trevor to act as a decoy while he and the others break onto Don's property. The red door (complete with Barbie's childhood handprint) leads to an old root cellar from prohibition days.
They enter the cellar, and find a hole in the wall leading to a very familiar tunnel. As each person heads in, they see a spiral of smoke appear and engulf them -- flashing them back to a specific memory. Barbie's memory involves the day the cellar door was painted ... and Melanie. Sam's memory is of a conversation with Junior right after Pauline's "death." Pauline's memory is more like a premonition; she's at the crater where they first found the egg in the '80s, and sees Melanie -- who says, "This is where it began, and this is where it ends. For all of us." Everyone (except Lyle -- where did he go?) ultimately finds themselves smack in the middle of the Chester's Mill lake ... they've made it in! Pauline takes off to find Junior, and heads to Big Jim's house. As she's looking around Junior's room, Big Jim comes up the stairs ... "Pauline?"