This book was a definite improvement over the third book, and the ending was pretty decent and showed what they would be doing moving forward. I thought it was interesting how he showed what would happen when Allie controlled the stone and how it would still control her. The path to get there was interesting and full of adventure that wasn't too fast like book 3, but I still felt like the very end of it was a bit rushed. My advice for the author moving forward is that he can come up with a pretty good story and series, but he needs to slow down the pace of some of these books and put in more transition, details, and for some of this, maybe a little more character emotion and dynamics. That did stand out as the characters never really changed or grew, but stayed mostly same based on their inner thoughts.
PS. I thought the step mom's name was Janet, not Karen.