This is a mixture of a few of my favorite genres: romance, action, sci-fi/post-apocalyptic with a nice touch of the enemies to reluctant allies to lovers trope thrown together into one enjoyable read. Throw in the librarian bit and I was pretty well sold on it from the summary. And it definitely ended ticking a lot of my "great read" boxes.
One thing I really thought was cool about this was the memos throughout. They really helped bring the story together and I found myself going back to various ones trying to piece things together.
Nina and Knox made a great team and couple and my favorite part of the story was the road trip their two teams took together. The two teams really compliment each other and I loved the way they came together. Also, Nina and Knox had a very sexy romance and a good emotional build-up as well.
My one gripe was that the end of the book kind of lost the track a bit for me and felt like a bit of an abrupt stop and pivot, but it still came together in a very satisfying (and slightly shocking) kind of way. I really look forward to the next book in this new series, as I really love all the characters and am super intrigued by all of their various back stories.