I liked the novel twist at the beginning. Pretty sure it's not a spoiler to say that the agent of change in this dystopia is a super-volcano eruption. The research that went into Mullin's speculation around that appears solid, and it added interest to an otherwise grim end-of-civilization novel. I don't know if I've read too many of them lately or if this one was especially depressing, but I felt more despair than hope after the end of this one. I see that there will be a sequel.