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

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.

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.