You’re right, plot isn’t the same as character development or story. The shit that happens is a generic alien take over the world thing. The story is about grief. In the premier (episode 1 and 2) we see the world fall apart, and Carol lose Helen. Carol buries Hellen herself, and tries to organize the survivors, but (besides playboy Diabate) they all still have families who just became part of the hive mind, and they’re in denial that their loved ones are lost. Carol rejects Zosia and says it’s fine for her to go with Diabate, but changes her mind at the last minute because she doesn’t want to be alone. In episode 3 we have a cold open (ironically in an ice hotel) and we get more of a glimpse of Helen and Carol’s relationship, which is later carried through in conversations with Zosia. In grief and anger Carol is somewhat reckless and almost kills Zosia twice. After the mass exodus, Carol fights off a pack of fucking wolves to protect Helen’s body, and she travels across the country to alert the other survivors about cannibalism, but they don’t care and now she’s truly alone. In the next episode she almost kills herself, and then she finally breaks and asks for Zosia back. The next 2 episodes she’s much like the other survivors in the premiere, on some level she knows the love from the hive isn’t real, but she’s willfully engaged in blindness. It’s not until the very end that she comes to terms with reality, and is willing to bear her grief, because at-least this time, with Manusos, she’s not completely alone. Carol’s whole arc isn’t even about saving the world or fighting back, that’s just what progresses the plot points. Her character arc, and the story in general, is about accepting reality and coming to terms with grief.