Marguerite was struggling in this book with the idea of an evil version of herself and if she had the potential for such evil. It was something she fought with in the previous two books but with other people, first Theo then Paul. I loved seeing her struggle with the same thing she judged the two boys over previously. She had to outsmart the evil Marguerite, Conley, and find a way to protect all the versions of Marguerite and their universes.
One of my favourite things about this series was getting to see all the different universes where Marguerite kept meeting up with Paul and Theo. Their fates seemed to intertwine in every universe, just in different ways. I was always waiting to see how they would find each other each time. I loved their dynamic between the three of them.
The action was really fast-paced without getting too rushed. There were a few times I had to force myself to slow down my reading speed because I was worried about missing key clues in all the science time travel talk but overall, I felt I had a good grasp on the technology and how it worked. Everything felt wrapped up in a satisfying way and it is definitely on the list of my favourite series.