Interest LevelReading LevelReading A-ZATOSWord Count
Grades 4 - 8Grades 3 - 6n/a5.3135683
Sophie battles the rebels—and recovers dark memories from her past—in this jaw-dropping fourth book in the bestselling Keeper of the Lost Cities series.

Sophie Foster is on the run—but at least she's not alone.

Her closest friends from the Lost Cities have gone with her to join the Black Swan. They still have doubts about the shadowy organization, but the only way to find answers is to start working with them. And as they settle into their new lives, they uncover secrets bigger than anything they’d imagined.

But their enemies are far from done, and unleash a terrifying plague that threatens the safety of an entire species. Sophie and her friends fight with everything they have—with new allies joining them—but every choice has consequences. And trusting the wrong person could prove deadly.

In this game-changing fourth book in the Keeper of the Lost Cities series, Sophie must question everything to find a truth that will either save her world—or shatter it.
Hardcover, 688 pages
Published on November 3, 2015 by Aladdin
ISBN-10: 148143229X
ISBN-13: 9781481432290
34 Book Reviews
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  • ilove2read
    ilove2readTuesday, April 21, 2020 at 8:18 pm55 stars
    This book was AWESOME! Sophie and her friends are joining the Black swan and things happen! There’s a plague that’s spreading and there’s Prenice rescuing, and much other stuff! This book kept me reading on and on and there were so many “oh my gosh!” Moments. I highly recommended this book to anyone who loves action and adventure.
    • 4usa
      4usaFriday, April 17, 2020 at 10:05 am55 stars
      I really really want to read this book but all libraries are shut down!😮
      • kotlcgirl
        kotlcgirlThursday, April 2, 2020 at 9:57 am55 stars
        Sophie and her friends are joining the Black Swan, the group that created Sophie! More suspense than ever in this fourth book of the series. Don't stop reading until you're at the end of the entire series!
        • jojo424
          jojo424Friday, March 27, 2020 at 2:38 pm55 stars
          This is soooooooo amazing. It's actually my favorite of all of them so far. Joining the black swan really got me jumping. Sophie, Fitz, Biana, Dex, and Keefe (and Della), go of on the most awesome adventure ever! They are hilarious in the furry pj's to mention that.
          • dragonrider13
            dragonrider13Sunday, January 12, 2020 at 4:33 am55 stars
            this series has been quite the adventure for sophie and her friends and so far just amazing this book was amazing by far one of the best i have read so far.
            • kkgautamm
              kkgautammFriday, May 31, 2019 at 10:27 am44 stars
              sophie and her friends are ready to join the black swan, but that adds a lot of hardship and responsibility to the work that they do. really enjoyed this novel, and can't wait to read the next one.
              • glitterclaws
                glitterclawsTuesday, May 14, 2019 at 8:19 am55 stars
                loved it loved it loved it you should read them all. there my fav
                • lains24
                  lains24Wednesday, October 24, 2018 at 3:23 am55 stars
                  • McFarlandNavyMonday, May 21, 2018 at 9:55 am
                    All of Shannon Messengers books are amazing including on her other series Skyfall.She is an awesome author and I can’t wait for her 7 book Flashback to come out.❤️😊
                    • emmaplays2546
                      emmaplays2546Wednesday, March 1, 2017 at 9:18 am55 stars
                      This book was so intense, and poor Callie. She sacrificed herself to save them. R.I.P Callie. :(