Summary from Goodreads:
In this third book in the Lunar Chronicles, Cinder and Captain Thorne are fugitives on the run, now with Scarlet and Wolf in tow. Together, they’re plotting to overthrow Queen Levana and her army.
Their best hope lies with Cress, a girl imprisoned on a satellite since childhood who's only ever had her netscreens as company. All that screen time has made Cress an excellent hacker. Unfortunately, she’s just received orders from Levana to track down Cinder and her handsome accomplice.
When a daring rescue of Cress goes awry, the group is separated. Cress finally has her freedom, but it comes at a high price. Meanwhile, Queen Levana will let nothing prevent her marriage to Emperor Kai. Cress, Scarlet, and Cinder may not have signed up to save the world, but they may be the only hope the world has.
There's so much happening in the book though at times it would feel slow because certain things dragged out but this was counteracted with the different point of views so we didn't stay focused on one/group of characters for too long. I didn't really like Cress and she joins Scarlet as a character that I wasn't fully invested in but didn't mind. I get that she was a bit weird because she was a prisoner up alone in a satellite, working for Sybil and Levana. Her fantasies were funny at times but, like she wanted to be, she came off as a slightly annoying damsel in distress. This just made me like Cinder even more...
Queen Levana's threats are taken to the next level and impending doom is about to strike Earth. How will Cinder possibly save the world (literally!)?