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.

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.

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."

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.

Big Jim conducts a census to see how long the town can survive on dwindling resources; acid rain threatens everyone.

A cave-in severs Barbie and Sam's path back to Chester's Mill during their investigation of a mysterious tunnel; a dust storm rages through the town, as Big Jim and Julia face off in a power struggle.