Having said all of that, my first question is whether all of this mythology is necessary. Put another way: is this part of a greater universe that you've been building for awhile, or is this a one-off story in a world you don't plan to return to? I ask because a lot of the background mythos of this world seems fairly irrelevant to the overarching story; for example, the Time Walker stuff. The only really important bit is that their father is sick, and they are tracking down Maya to heal him. We as readers don't necessarily need to know the elaborate details of why he is sick, particularly because it doesn't contribute much to our understanding of the story. It helps, but the fact that one of the characters has to explain exactly what it is and how it works and how it works to make him sick sort of takes away from it a little. A fairly significant amount of time is devoted to a point which doesn't really matter to the overall story of love and betrayal and trust.
If you are sold on this Time Walker thing (and I can see why you may be; it's a fun concept), I would suggest trying to find a simpler way to incorporate it. Even just paring it down to: "We're Time Walkers and it's taken its toll on my father," is almost enough; your readers can take a guess as to what a Time Walker is. It's not a hard one to figure out. But really do consider taking it out, if for no other reason, then I think it will neaten up your story. Way too much time is needed to sit down and explain to your readers about how the world ticks (not just Time Walkers; all the details of Maya, too), and it takes away from the immediate drama.
Another note on the mythology getting in the way: when Josh tries to get her to protect him, and in doing so turns her against him. In this climactic, dramatic scene, the final showdown of the story, we have Maya pausing to explain to him why this isn't working. Not only does this seem like an obvious nod to the reader (why on earth would she stop to explain to this villain the dos and don'ts of using her magic?), it also detracts from the tension of the scene. My suggestion would be to employ that oft-used technique, where a similar situation comes up earlier in the story and Maya has a chance to tell us how this magic works, so we're prepared for it when Josh makes his lethal fumble. Even just a bit of dialogue earlier on, where Joshua maybe says, "Parker is planning to use you to defend himself," and Maya thinks, Yeah, right, this would never work, insert magic explanation here. Except, you know, not so haphazard as my example, but you get the idea.
Those are my big issues with the overall worldbuilding, although as mentioned before, you do have some really great ideas packed in here. I'd also like to note that the motivations of the family don't seem to be very well-defined in terms of hunting for Maya. Especially because we learn that the father spent a great deal of his life hunting for Maya. Some of this is difficult because we are fed a lot of misinformation from Josh so we don't know exactly what happened in this whole 'murderous rampage' scenario. I think the biggest things for me are: What makes Maya's magic the only thing that can heal their father? Why could Parker not have found an easier way to contact her than tracking her down? And did their father spend his lifetime searching for Maya, and if so, why? Especially if he only got sick later in his life? Making these motives clear would help the story greatly, just in terms of understanding the characters and how they function.
A few other overall notes about the story. First off, and this is totally a personal dig, but I hated the character Joshua being called 'Josh'. As far as I know, the nickname 'Josh' is a fairly recent occurrence (recent being anywhere from mid-twentieth century onwards) and in my head, 'Josh' is the name of a preppy young fellow who just graduated high school and is loved by all the ladies. Now, obviously this is my own subjective colouring of the name, but I find it difficult to believe that someone who was born in a manor at the dawn of the 1800s would go by that moniker. Joshua, I can believe; Josh, I can't.
Another note about the twins, that I think someone has already made: twins don't in fact have the 'same blood'. Similar blood, sure, or even familial blood, but not the same. I would suggest tweaking just that sentence to fix that.
Other things: the very opening feels a little too vague, especially because we are just being introduced to the rules of your world. When you say that she doesn't know where she is, not even what day, I sort of imagined she was hopping from century to century in that moment, and so she wasn't running through space but through time. I feel like the reader needs a bit more immediate clarity of her situation; even a throwaway comment like 'twigs snapped underfoot' or 'branches whipped at her face', some quick description of her surroundings so that we can place ourselves with her. Otherwise, at the beginning, it's hard to tell if she's running through a field or down a highway (which is sort of what I pictured on my head), or a space station or across the planet Mars. Given the immediacy and tension of the situation, I don't expect a lengthy paragraph of her bearings, but just some hint to give us a better understanding of where she is.
This also threw me off:
or the imaginary knife embedded in her foot. Oh, the knife was surely real but
I think you mean to say 'invisible' or something to that effect, but it's sort of off-putting to be told it's not a real knife in one sentence and then to be told, no, just kidding, it is real. Stick one and stay with it. This is especially important because, again, we're still trying to find our bearings in this world and figure out what the rules are, so it's totally possible that she's crazy and the knife isn't real.
I found the whole he's-the-real-hunter thing a bit predictable, but apparently I'm in the minority. I do however think that you don't need to outright state, or at least in such plain terms, 'this is what's actually happening':
The truth suddenly struck Maya; when Josh had been telling her about Parker, he’d actually been speaking about himself! He was the tracker on her trail, and although Parker was also, it was for different reasons. Good reasons.
If you feel like you need to explain it to your readers (and I really don't think you do; I think they can probably piece it together), I would suggest just going with, 'It hit her. Joshua had been lying all along,' or something to that effect. Just a sentence or two. You definitely don't need to spell it out to the reader; it comes off as a bit condescending and sort of sloppy, like you don't trust them to have brains.
Quick thing about this scene: it doesn't reeeeally make sense that Joshua is confused that his parents are gone. Especially if he just killed one of them. It's sort of unclear what happened here, or why he thought his father would just stay put. (Sure he's sick, but if he just killed the mother, wouldn't his father drag himself away from the scene?) This didn't strike me as very sincere.
I also found it extremely difficult to buy the ending, that Maya would stay and take care of Parker. Especially considering a person who looks just like him tried to kill her; I feel like she would have a few residual trust issues. This ending feels to neat, everything wrapped up with a bow and a hint of romance. For someone who appears to have been on the run for so long, to give in to a family which obviously has some problems telling the truth seems way too convenient.
...wow, this review ended up being a lot longer than initially intended. Well, good luck with the contest and good luck with revisions. If you have any questions or need some clarity about anything in this review, feel free to PM me.
