I was planning on reviewing each book separately, but because I read them all back to back on my phone I couldn't remember what happened in each book so I'm just going to review the omnibus edition.

This review might get a bit ranty.

You may remember my review of the 1st book in which I was annoyed that it was so compelling. This feeling continues into the rest of the books. They are messy and confusing and unrealistic (we'll skip the part where someone tries to tell me that stories about alternate universes are all unrealistic and settle on good stories being internally and logically consistent and these not being that) and I wish I wasn't so interested in Audie's life. I wanted to know that she would be okay at the end, and that her and Daniel would stay together, because I liked her!

So in the first book I had assumed for a second that the parallel universes had split off after Audie/Halli were born which would then make sense why they were identical, but then learned that their parents and grandparents were very different so that couldn't be true. In the next books, we learn that the universes actually split just after WWII, where in Halli's universe, a bunch of scientists all around the world signed a "peace pact" saying that they would not pursue research that could lead to the development of weapons. Which seems a little hand-wavey to me because technically anything could be used as a weapon, which they mention in the book but don't follow up on so I have no idea how this pact worked out in that universe...except that they don't have space travel because all of the rocket research could lead to bombs. But they have amazing horticulture because I guess nothing to do with biology could ever lead to a weapon (except for biological weapons but we ignore those I suppose). And that universe obviously decided to err further on the side of safety over personal freedom since everyone has a tracking device implanted in their bodies (which everyone can access before you're an adult, after you turn 18 you can remove people from the list of who can track you but presumably the police/government could access anyone's information whenever). Despite these HUGE CHANGES from Audie's universe, Audi and Halli's grandparents (with wholly different personalities) managed to get together and have genetically identical children born at exactly the same time, who then developed their own wholly different personalities and managed to get together to again have genetically identical children born at the same time. It's IMPLAUSIBLE.

So Audie tried to save Halli from death once, and in doing so she ended up in Halli's body with Halli ending up in Audie's body in their respective universes. This is never explained. It just happened because Audie was distraught at seeing Halli die so she panicked and this ended up happening. So Audie is trying to get back to her old body while also trying not to mess up Halli's life too much, and Halli is terrible at waiting so she just starts making plans to ditch all of Audie's family and friends and live in the wilderness. I hate Halli in these books. She's so self-centered it's painful. Her grandmother taught her to be that way...basically, everyone needs to look out for themselves and if they can't then they deserve whatever comes to them. There are a couple stories that even demonstrate how Halli's empathy was stamped out by her grandmother, for example, there's a guide they know who is a terrible guide and many people have died under his watch. This makes Halli upset, she wonders why her grandma wouldn't warn the people who keep paying him to guide them, and she basically says that people only change when they want to change and the people who signed up to be guided should have done their research. So instead of, say, reporting him to some oversight organization or the police or something (this universe seems like they'd care even more about stuff like that than ours), Ginny is like, whatevs, they're not you or me, so fuck 'em. And Halli internalizes this attitude and therefore only cares about people she likes. Which means that when she's in Audie's life, she's rude to all her friends and makes plans to leave them all as soon as possible. She hates anyone who tries to impose rules on her, which she did in her own universe too, but doesn't take into account the completely new circumstances which may involve a little bit of tolerance and thinking about other people for once. It's been ONE WEEK since Halli has been in Audie's body and she's already like, Audie can't do anything for me I must make this life my own. Man, you SWITCHED BODIES AND UNIVERSES. Give it some time, this can't be an easy problem to fix! So I basically don't give a shit about Halli. She's not even dealing with anything important, she just needs to go to school and try her best to act like Audie.

Meanwhile, Audie in Halli's body is trying to fix the universe mix-up while dealing with the fact that her parents want to buy back the 49% of their company's shares that Audie has before she turns 18 and can make that decision herself, so Audie is trying to prevent Halli from losing her fortune at the same time trying to avoid her overbearing parents at the same time trying to figure out how to get back to their own universes...AT THE SAME TIME dealing with some relationship bullshit that I was 100% not into. Will is the dude she's been in love her for blah blah blah I don't give a shit, and his counterpart in Halli's universe is super into Halli and Audie is pretending to be Halli but she's into Daniel, but alterna-Will is just soooo good-looking or whatever and Audie keeps being like, I tried to not make out with alterna-Will because I'm into Daniel but then he looked at me and I just had to make out with him! No, girl. Have some self-restraint.

Anyway Audie ends up dying because she tried to stuff her consciousness into her old body with Halli already in there and that makes you die. Because. So she dies and as she's dying I guess she reaches out her mind into blah blah and wakes up again as Halli back in time so she can do it all over again. And THIS time she doesn't make out with alterna-Will, and she realizes that this universe is slightly different from the last one because she stayed with someone different and her dog doesn't like alterna-Will and as it turns out all of these things are true because Audie somehow changed the past from the future without knowing it. And they go through all this ridiculousness to try and get everything back to normal, and in the end, she just had to think about switching her mind with Halli's and then IT WORKED. I mean, they needed to have access to a universe-bending machine (or whatever) that a professor built and used to switch universes back in the 40's but really it seemed so obvious that Audie should have tried it before. So anywhere they're like, oh yeah, everything is fine now. Except no one is thinking about the other universes that they created...like the universe where Audie died in Halli's body?!? THAT HAPPENED. That didn't just disappear, that is a universe in which Daniel (and the entire world) is in mourning, and then another universe in which Halli is trapped in Audie's body forever and has betrayed all her family and friends and I guess is living happily by herself as an adventure guide or whatever. Which, I mean, Audie's current consciousness isn't living that universe, but she also visited a universe in which Halli's grandmother didn't die but Halli did, so Ginny is living sadly without her granddaughter. So I'm just saying, Audie could totally visit the universe in which she died in Halli's body and see how sad everyone was. Not that she should have done that in the book, but it seems weird that she didn't even acknowledge it. Really, she has a get-out-of-jail-free card now because if anything goes wrong she can just slip into a different universe where it didn't go wrong anymore. It's just strange that the fact that she actually did die isn't mentioned again. Audie seems like the kind of person who would think about that and be a bit sad for the fact that she caused that to happen, basically. And it seems like an obvious consequence of there being multiple universes.

So I found all of the alternate universe and travel between universes stuff to be really sloppy. This is supposed to be a science fiction series, and the first book at least tried to explain things using science, but it sort of just broke into a series of increasingly ridiculous reasons that seemed invented either to increase the tension in the book or to explain away a plot hole. It was overly complicated and didn't seem very consistent. I started reading it because that seemed cool but it turned me so completely off that I started skimming through a lot of the explanations of alternate universe travel. I just wanted to know that Audie would be happy. It was an easy series to read, and written well, I just don't like hand-wavey "science" explanations for things. Either make things actually scientifically plausible (alternate universes are fine, just make things internally consistent!) or don't try to explain things using science. ( )