A frustrating end to a frustrating series.
80% of this book is made up of replaying scenes we've already read from a different POV (boring and unnecessary - it added nothing to the story) and slowly going through the motions of explaining obvious plot points that have been telegraphed from very early on, (the professor is alive, Dorothy didn't actually kill Ash, etc, etc.) But in the end, the stakes seem so small. They prevented the extinction level event earthquakes from happening in the future by ending time travel, but they did nothing to fix the past or present. Millions of people are still dead because of them, and the west coast is still a postapocalyptic hellscape, so it's not exactly a happy ending. Oh, and that immature backstabbing little weasel Roman isn't actually dead, so the one thing I liked about book 2 was undone in book 3. Great.
There is a logical fallacy at the core of the series that never made sense. I kept waiting for it to be explained as the key to saving everything, but in the end I think it was just a lazy plot hole. In the first book, Dorothy has a prememory and when she sees it start to happen, she changes it by cutting off what Roman was going to say, making the conversation go differently. So if she can change a prememory, why is everyone so convinced that Ash can't change his? And why does Dorothy think she needs to stab him so they can both go back through time together? She has a freaking TIME MACHINE! Idiot.
Really, this whole series should have been one book. 90% of their problems are caused by not communicating, which is just lazy writing. If the characters had just talked to each other, most of the conflict would have been solved or avoided completely. Ash could have explained why he seemingly rejected Dorothy instead of setting her on a path to become an evil gang leader (albeit, a weak, terrible one.) And several people figured out time travel caused the earthquakes - why don't they ever try to spread that around?! At the very least, Ash should have told Dorothy. And the professor said he stayed back in time because he didn't want to risk taking even one more trip through the anil because each trip caused damage....but what did he think was going to happen back in the future? Ash was making trips for a whole year to look for him, which he should have figured would happen. Did he not consider the impact all that travel would have?? So many plot holes.
This book dragged on for way too long, given how little happened. Yet it didn't spend time on the things I actually wanted to see, like character growth and to see Dorothy turn into a person who could be worthy of Ash. I wish there had been more romance in the series as a whole. The romance was very flimsy and instalovey, and the two of them only have brief interactions in the last two books. So disappointing.
I'll admit, the books are engaging - I was sucked in to the story and breezed through all 3 books pretty quickly, but after the end of the first book, I was hate-reading because everything that happened made me mad. Not a very enjoyable experience.