The residents of Chester's Mill find themselves trapped under an enormous, transparent dome. Panic escalates as resources dwindle rapidly.

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