This was a solid sequel to "The Outcasts." The Herons are on their own now (with Thorn), and I loved seeing how they worked together as a team, anticipating Hal's commands and everyone willing to step in and do their part and cover whatever needs come around. Hal has some brilliant ideas to give them the upper hand in their battle.
The addition of Lydia was nice, she seems interesting enough (very much like Cassandra/Evanlyn-beautiful yet independent and courageous, and also skilled and resourceful with her weapon of choice). I can see the love triangle heating up, which looks to be a fun addition to the series. I do have a problem with how "stunningly beautiful" the leading ladies are in this and in Ranger's Apprentice. I appreciate that they are skilled and courageous, but must outward beauty also be dragged into each major female character? I feel like it is rather sexist(there's no mention of how good-looking Hal or Stig or Will or Halt or Horace are), and also reinforces the idea that girls NEED to be beautiful to be attractive or interesting to men, which is a terrible message to send to young women. They get enough of that from Hollywood and magazines. It also reinforces the idea that men are chiefly attracted by looks only...and maybe, sadly, that's true? I don't know, I'm not a man.
Also, I really enjoyed the character of Thorn-his backstory, his downfall, his recovery, his renewed purpose. In this book (compared to the first book), he's more his own personality, and less like a 're-invention of Halt, with a different backstory.'