For the first several chapters, I couldn't wait to finish one page to get to the next. The writing was that good. However, after Sara meets up with William, things get a little far-fetched, at least for a while.
Sara is a half-vampire/half-human, orphaned and now in her twenties, living by herself after her Aunt's death. She's been dreaming of William, someone she feels is real and that she'll someday meet, but her dreams are also haunted by premonitions of terrible happenings.
In order to remain invisible to the "seekers", creatures she knows little about, she's been taking a serum. However, due to her nightmares, in an effort to stop dreaming, she's been playing with the formula and all bets are off.
This is where things start getting a little "emotionally weird" to this reader. William, the man of her dreams (literally) who is also half human/half vampire, shows up and tells her they must leave, that the seekers have found her due to her misuse of the serum, and are on their way to capture her, something she won't like. The entire first meeting with William is so off the charts I can't even put words to it. The emotional swings are not handled/written well and I'm sorry, the increase of serum injections smacks too close to drug use (I know, it's just a book and there is a reason behind the entire serum-use, but still, enough is enough).
Now Sara and William are on the run, trying to evade the seekers, while making it back to a safe haven, deep in the Amazon jungle. Here once again we find over-the-top emotions running wild and multiple, frequent serum injections (used to keep her invisible to the seekers). Things do pick up for the good from here on out though. I'm not going to say any more as I don't want to give away any of the story.
Now, in the books defense, since to this point you probably think I absolutely hated it. I didn't: The storyline/plot was an excellent one and I found myself, even with the emotional instability of the story & the over-the-top use of a serum, eagerly turning pages, wanting to know what happens next. There was an excellent cliff-hanger and a "will he/won't he" ending that left you hanging on every page.
Yes, the book could have been better. There were parts that lingered on certain topics too long, the emotional swings were too much to handle and poorly explained, and the book slowed to a crawl at some points. But, a good plot, fully developed characters (even supporting characters were well developed), and an excellent ending fully redeemed this book.
All in all, a decent read and something most people will enjoy.