Chester's Mill has a monarch infestation which threatens their crops and food supply. The butterflies collect new Julia and over Angie's body, while the caterpillars consume too much of the town's fields.
Junior finds Angie's body and suspects his father killed her. He's not willing to forgive Jim for what he's done so he's an easy target. They find a bloody female footprint at the school and it belongs to the mystery girl. Junior and Joe go to kill her after she's been apprehended, but they are stopped.
Angie had bruises from a large male hand on her.
Barbie helps Joe mourn the loss of his sister and convinces the young man to go to her funeral.
Junior finds Angie's bracelet and believes he killed her during his blackout.
Rebecca burns fields to stop the infestation and then Barbie uses pesticide to save the rest.
Rebecca and other residents see Big Jim as a hero after he sacrificed himself. They believe he saved them.
In the end, Rebecca tells Jim that there's not enough resources under the dome and some residents must die to save the others.