Lucinda (Lucy or Lu) and Margot are something else entirely, and we've waited through the first two books. They were conjoined twins, separated at birth- and their separation scars resemble a lock and key. Lucy is able to sense Margot's feelings, and this comes in handy when Margot disappears. Lucy goes to the True Borns for help to find and rescue Margot. Now, in the aftermath, Lucy feels fractured- Margot is blocking her out. Margot seems traumatized by her experiences (which makes sense- she was kidnapped and her eggs were harvested and turned into some sort of plague "cure"). Things are more complicated than they appear, as we find out later. Add to the mix that people are saying that together, somehow, Margot and Lucy are supposed to be the key to the permanent plague cure, and we have some plot intensity.
Luckily, we get answers about what exactly Margot and Lucy are, and how they tie into the prophecy/plague cure. If you enjoyed the back-and-forth between Lucy and her instalove Jared, you are in luck because it continues in this book. I loved their romance and the idea of the two of them together (plus they had so many steamy kisses!) but I wished they would quit it with the "but we can't/shouldn't be together"- it seemed like they were pushing/pulling a lot. The love triangle with Ali is back, and it takes some turns that really surprised me! I won't say more to avoid spoilers.
I enjoyed the book overall, but I felt that the ending was too abrupt, and I would have liked to see things play out a little further. It almost felt like there would be another follow-up, but I doubt it as this is the third book in a trilogy. We are left with the impressions of what will follow, but it's not as clear/determined as I would have hoped (an epilogue or something for full closure would have been nice in my opinion). The writing is great- fast-paced and enthralling. I think fans of the first books will enjoy this finale overall (although I will mention as a warning that there is a main character death that shocked me- and it's very sad!).
Please note that I received an ARC from the publisher through netgalley. All opinions are my own.