I wasn't quite sure what to expect from this book that I decided to read on a whim. A mix of time travel and modern-day politics? Okay, let's see how the author handles it. To my surprise, he handled it very well indeed. Usually anyone who decides they're going to take on 9/11, gentrification, racial issues, and historical revisionism has an axe to grind, but Mullen's axe is hard to figure out. What politics there are in the novel are not overt, which means you can sit back and enjoy the story, and it's a very good story.
Basically, there is an agent "Z" from a future society whose job is to prevent a group of would-be revisionists from Z's time from changing the past and thus destroying the society of the future. Initially Z is presented to us as a good guy defending an advanced, peaceful society from possibly devastating historical changes. As the story goes on, however, we learn that Z's society isn't as wonderful as we've been led to believe -- indeed, as Z has been led to believe. Increasingly, he questions his mission and the truth behind it, and through flashbacks we learn just how dark the future really is.
Paralleling Z's story is that of a former CIA agent in our own time who, like Z, increasingly found the ideals he was supposedly working for in conflict with the work he was actually doing. There is also a young Washington, D.C. lawyer searching for the truth about her younger brother who died in Iraq, and a domestic worker trapped in Washington by her abusive employer who has diplomatic immunity.
Weaving all these different threads together would be complicated enough in a plain old thriller, but as it is a science fiction novel as well, I feared it would either be a mess or something resolved with some kind of deux ex machina. In fact, everything ties together quite well, and the overall tone of the novel does not even feel that much like a science fiction novel, more like a literary thriller. This would be a good book to hand someone who likes mysteries and thrillers but not science fiction particularly. The time travel elements are so unobtrusive you don't even find yourself worrying about the sorts of things you usually do in time travel stories like the Grandfather Paradox, etc.
There is some philosophizing by all the characters, each of whom is basically a good person who sometimes acts out of self-interest and has to weigh how much guilt and responsibility they can bear. Overall, a good and somewhat intellectual read with a fast-paced story. This one really surprised me. Recommended for a change of pace for anyone who likes science fiction, and worth trying even by those who don't.