(Whoops, forgot to log this one when I finished it.) 
 This book was brutal. It's been a really strong series--it's not shy about the ugliness of this apocalyptic world. People are pulling together into communities and protecting each other--but what are they protecting each other from? Alex can see what needs to be done, but at 16 years old he's not about to take over as a leader--except that he doesn't have much of a choice, when it comes to it. 
 He and Darla have been a team since shortly after the Yellowstone supervolcano blew, and they keep tightening their bond. Family relationships are strained; people give and take and sacrifice for each other. They still have hope for their communities, and their whole new civilization. 
 This is the conclusion to the series (I think) and it's gritty and harsh and dark and still hopeful. Ashfall has been a top-notch Disaster series, and I'm kinda sad that it's done, but at this point I'm pretty sure that Alex, Darla, and the rest of their new city will be okay.