"The Black Key" is an intense finale to the Lone City trilogy. Violet has escaped the city and is training other surrogates about their powers and the legacy of the Palladin. I read the second book right after its release, so I wasn't sure if I would remember enough to delve into the third book without rereading the first two. However, Ewing does a fantastic job of taking the reader by the hand and reminding them about the events in earlier books without overdoing it. This book really focuses on the battle and leaves the personal insights and romance behind. This book is about a revolution and we get peeks of the larger battles looming, as we are still focusing on Violet. Overall, I thought it was a good end to a strong series.