Originally post at Vampire Book Club 
 The end of Dissonance found Del losing the boy she loves and being betrayed by her grandfather, the person she trusted the most in her family. Resonance picks up after the Free Walkers contact Del and inform her that Simon survived the cleaving of the Echo. Thrilled at this news, Del wants to see Simon right away. The Free Walkers have other plans, however, and before a reunion can take place, there's things they'll need from Del. 
 The Free Walkers are rebel Walkers. They disagree with the Consort's cleaving of Echoes, feeling that Echoes are people too and not just mindless copies of Originals. Therefore in their minds Cleaving kills thousands upon thousands of people. Free Walkers want to preserve those lives. For years they've waited for the perfect opportunity to strike back at the Consort and now their time has come, and coincidentally Simon fits perfectly into their plot. Del comes to discover that when it comes down to something you're fighting for, even if it's ultimately right, sometimes the lines blur between good and bad. 
 Dissonance and Resonance definitely need to be read together. If you were on the fence with your feelings about the first book, the second book would probably turn them around. I think these two books could very well read like one long book, if Erica O'Rourke wanted to put readers through almost a thousand pages at one time that is. Thinking of it in that way, I'm kind of glad the story was broken up into two books. 
 Del's stubbornness and reckless actions in Dissonance turn out to be an asset in Resonance because it keeps her from falling under the spell of the Free Walkers and being taken advantage of. While their ultimate goal may be a very noble cause in the end, they're a little lackadaisical when it comes to the lives of other Walkers. In that regard they're just like the Consort whose ideology is the protection of the Key World at all costs. For the Free Walkers it's the destruction of the Consort or bust. 
 Even though I wasn't really on board with Del's feelings for Simon in Dissonance I have to hand it to O'Rourke for writing a pretty uncomplicated relationship between the two here despite the various opportunities she could have taken to throw in a little angst. 
 Simon's storyline dealing with the fact that he's a Half-Walker proved to be the more interesting part of this book. O'Rourke throws in some twists that, looking back at the first book, should have been glaringly obvious, but since I missed it, I ended up finding rather clever and just reinforces my point that if you're going to read the first book, you need to read both books. 
 I definitely think that Erica O'Rourke could continue with other stories in this world even if Del is not the main character. This only takes place in one city in the U.S., but there are Echoes and Pivots all over the world. I'd love to read how events within this duology affect Walkers elsewhere.