Julia uncovers the truth about her husband's disappearance and unravels some of Chester's Mill's darkest secrets. Meanwhile, Maxine shows Barbie how she plans to take control of the town.

Barbie turns to his father for help contacting Julia but realizes that he may not be trustworthy; Big Jim declares himself sheriff of Chester's Mill.

When Big Jim is captured by Aktaion, the dangerous private corporation that’s descended on Chester’s Mill to harness the Dome’s energy capabilities, he’s forced to manipulate Christine for information about her agenda. Also, when Joe and Norrie question the town’s new rules, they find themselves in a dangerous face-off with the increasingly unstable residents.

The Resistance, the citizens not under Christine’s control, join forces with an unexpected ally: Hektor Martin, the nefarious head of Aktaion. Despite Hektor revealing more about the Dome’s origins and helping to strike back at it, Big Jim and Julia still worry he will betray them. Meanwhile, Hunter receives encrypted files that give disturbing insights into the final effect the Dome will have on the infected townspeople.