This is good modern horror. No SF or Fantasy mix at all. Oppressive and thrilling start, giving us thousands of questions and immediate care for Mallory and her two children. There are few good answers to be had by the end of the novel, but that doesn't matter. It's a thrilling and emotional tale set between the extremely harrowing present, lost in required blindness due to the unknowable tragedy that surrounds them, and the past, as we get to see how she survived up to then. 
 It's a simple tale made vibrant with so many questions. 
 Why are people going crazy and murdering everyone and themselves after seeing what is outside? Why has it struck the whole world? If you're lucky enough to have closed your eyes or otherwise blinded yourself, then you have the chance to live, but the questions remain and even those tend to rip off the blindfolds. 
 So simple. And yet, quite terrifying when you're in the middle of it and desperate to survive. Oh so oppressive. And chilling. This is what good horror always ought to do to us. Question, reason, fear, and survive. But mostly question. The answers are rarely the ones we want and the fact is, we rarely get good answers anyway. The trick is always to question and always hold on. It doesn't matter if its your sanity, a blindfold, or your children as you search for your next meal, avoid the crazy birds or the crazy dogs or the rivermen that cajole you into just opening your eyes, "It's so beautiful...": The point is to hold on. 
 So damn sweet.