Honestly I didn't get "into" the book until I was about 80% done. The cliffhanger was good, but it also felt stale. We've been there before (SPOILER ALERT) with Eli pretending to be Owen and it seems like that's where we'll head for the fifth book, but now you have the added layer of Sage and Jackson, so it might play out differently which will be refreshing. I am fully committed to the series so I will for sure be reading book 5 when it comes out.
*Further SPOILERS Ahead*
Beginning: We start out with both Eli and Harper in custody and taking beatings. Been there, done that. Celdon is still trying to play spy within Constance. And Sawyer is blissfully ignorant (mostly) in H&R.
Middle: Eli and Harper are out of jail and into full love mode! Exhibitionist much? Celdon found out who his mother really was. Sawyer is starting to feel real uncomfortable in H&R under the scrutiny of some rather questionable "patients".
End: Sawyer is patient zero. Celdon has been fully committed to Constance...whether he wants it or not. Eli and Harper are out in the Fringe looking for a cure. Owen was captured, but Eli and Harper vow to save him!
What will happen in the fifth and final installment? I can't wait to find out!