I read this title on my Kindle, courtesy of Netgalley. 
 The first thing I noticed about this final title in the epic Passage trilogy is how smoothly integrated the backstory/catch-up tidbits are with the current story. It's the perfect amount, as too much can get boring and feel unnecessary, but not enough and I'm struggling to remember what I read years ago. The process is slow, and doesn't throw all the characters at you at once. 
 Then we get to, I think, 10 years after The Twelve. The people haven't had a viral attack in a long time, and some are even getting complacent. New and smaller communities have been established, and new characters (some born in between the books) are introduced. 
 My favorite part of the book came too early on, about 15% in. We learn about Zero. His backstory fascinated me; Cronin's wondrous writing talents really come into play here. Unfortunately, that section is over too quickly. 
 Next we move into the meat of the story, the re-emergence of the virals. We get a front-seat view when the characters begin realizing that things are going to get bad. The opinions on how to deal with this vary, and the tension that builds up is nearly palpable. 
 Of course, there will be a final showdown, since this is the end of a series. Several battles accomplish this, and it's probably what keeps this one from getting a higher rating from me. I felt like this dragged on and took far longer than necessary. Ack, I just checked, the book is 624 pages! No wonder I feel this way! Maybe I would have liked it better if more had been added to the beginning and end areas, and spread it all out over two more books instead of this one. Or if this one was just edited down some more. 
 So, too much viral and Zero battling for me. 
 I didn't expect the ending (maybe it was the epilogue, by that point), but I liked it. It gave me some peace as well as more things to think about. Overall, a fantastic set of three books that I highly recommend.