Finally. The Valley of Shadows is set in John Ringo’s Black Tide Rising zombie apocalypse series; and if you haven’t tried that series out yet, I recommend it. In Black Tide Rising, it’s not so much the zombies that are the problem; it’s that most of the people are gone and the remainder are constantly stuck busting their asses to keep civilization running. So, not nihilistic: just very, very grim. …And lots of guns! Which makes things less grim, at least to read about.
Anyway, The Valley of Shadows (written by Ringo, and Mike Massa) takes up a part of the story from the first book of the series, and runs with it. I look forward to finding out to those particular folks. I kind of wondered.