Following Duke's death, his house catches fire, forcing the town to rally together to form a bucket brigade. Elsewhere, Junior ambushes Barbie, while Dodee and Phil pick up a military frequency.

When a former deputy goes rogue, Big Jim recruits Barbie to join the manhunt to keep the town safe. Meanwhile, Junior is determined to escape the Dome by going underground.

The people of Chester's Mill panicked state when a meningitis outbreak hits the community, threatening the already scarce supply of drugs. Meanwhile, Julia continues to seek answers to her husband's disappearance

The Chester's Mill residents receive an unexpected visit from their loved ones on the other side. Meanwhile, the community braces for a threat from outside the Dome.

When the town begins to run low on water, the residents of Chester's Mill begin to fight for the remaining resources. Meanwhile, Julia discovers a strange connection that two of the town's residents have with the Dome.

Big Jim takes matters into his own hands when he feels his authority slipping away, and the Dome displays its power when a life is taken just as a newborn arrives.

Junior stands up to his father and is shattered when he discovers the truth about his mother's past. Meanwhile, Julia learns firsthand the powers of the "mini dome."

Barbie and Big Jim realize their lives are more intertwined than they knew when a mysterious woman makes an appearance in Chester's Mill.

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.

Big Jim turns the town against Barbie when the truth about his past is revealed. Meanwhile, Maxine makes it personal when she confronts Barbie’s closest ally.

While the manhunt for Barbie continues, Big Jim gets the residents of Chester’s Mill riled up and the town demands justice for all of Barbie’s supposed crimes. Meanwhile, Joe and Norrie must find a new hiding place for the mini dome.

Secrets of the Dome are revealed and Big Jim is determined to put an end to Barbie once and for all. Meanwhile, Junior, Angie, Joe and Norrie discover who the Monarch is after receiving a shocking visit from a familiar face.