There are two main conflicts in Deception: the problem of what to do with all the survivors, who are still being pursued by the nefarious Commander, and the alarming realization that there is a traitor in their midst. The resulting balance between action-driven tension as they flee the Commander's army, and internal tension as Rachel and Logan try to suss out who has betrayed them, was masterfully handled, and kept me turning pages long after I should have turned out the lights and gone to bed.
Personally, my favorite part of the book was the murder mystery. C.J. gives the reader enough clues that it is possible to guess the murderer (I did), but you're never 100% sure you're right. I think that's the mark of a well-handled mystery. I don't like it when the answer comes out of nowhere, nor do I appreciate it being so obvious that it kills the tension. There's a fine balance, and Deception does it well. The fact that it performs this feat while the characters are fleeing through the wilderness and fighting armies and blowing stuff up and cowering from dragons just makes it that much more amazing. And when you do find out who the murderer is, it comes with a few twists of its own that perhaps a more savvy reader could have guessed, but took me totally by surprise. In a good way.
I also really appreciated that Deception did not fall prey to the common practice to break up the two main characters who spent a good chunk of the first book coming together. A lot of times, it seems storytellers get bored with functional romantic relationships, so they throw in DRAMA and pull the characters (that they spent so much time convincing us were MFEO) apart. Not so in Deception. Rachel and Logan mature both as characters and as a couple, and like most couples who have weathered a few storms, are allowed to get upset with each other and disagree, without it having to mean they CAN NO LONGER BE TOGETHER EVER, OH THE ANGST.
Speaking of angst, Deception does not shy away from high stakes and raw emotion. Much like a certain wagon scene in Defiance, one chapter needs to have a warning label to have a box of tissues handy, or at least change your shirt into one that can double as a tissue. A lot of times in books, and perhaps in YA in particular, it seems that the Strong Female Characters can't show their emotions. They can't grieve their losses or feel broken from pain. In these books, I appreciate that Rachel is strong, but also feels so much. Emotions don't make a character weak. Neither do tears. And I think it speaks so much to the character of Rachel that she can hurt and weep and break, but then she gets up and keeps going. She carries her losses with her, and they make her stronger. But because the reader is in Rachel's head when horrible things happen to the people she loves, we get to feel all that strong emotion right along with her.
So. As I said. Box of tissues. Change of shirt. You have been warned.
I could go on for ages about how much I love this series, these characters, this world, but I think you've got the gist of it. Adventure. Murder. Dragons. Villainy. Romance. Swordfights. Treachery. Anguish. Triumph. All stirred up together in a fantastic, masterfully executed whirlwind of action and tension and twists and emotion. I couldn't put it down.