In The Last Town On Earth
, near the end of the Great War and during the Spanish flu outbreak, a remote, collectivist mill town in Washington state closes itself off to the outside world to avoid the ravages of disease. A starving soldier arrives and upsets their plans; actually, there are two starving soldiers, and each separately arrives and upsets their plans twice, but whatever. It turns out neither soldier really has anything to do with anything, that the flu inflitrates the town for reasons having nothing to do with intruders, and kills a bunch of people without any real narrative value, and I think the point of the story is that it's sometimes ok to shoot people. Whatever it is, I don't think it's any more complicated than that.
But enough being harsh. The beginning of the book seems like the beginning of a novel someone writes and then sticks in his drawer for years because he can't figure out how to continue it, then finally does. It hits its stride after a few chapters, and is written competently, and the story carries you along comfortably. There are interesting nuggets of American cultural history here, even while the story itself is a little thin. The characters are capably fleshed out, with an exception or two, and no one does anything unbelievable.
Ultimately, the book is unsatisfying. There is an abortive romance whose end isn't dramatic or sad, it's just disappointingly "there"; there is a brooding, conflicted character whose conflict is resolved but not in a terribly interesting way; there are hints of interesting socio-political subplots that never bear fruit. It's possible that Mullen imagined a world, or a town, where nothing much interesting happens. That's realistic, there are towns like that everywhere. Just not something you'll find rewarding.