Okay, so I read a book a year or two ago, and I cannot believe I can't remember the title, but I really don't.
I don't remember the character's names, but the main hero was a female. There was a male character as well, and a witch along the lines. I remember various and odd scenes in the book, and I remember some points in the plot line, but I cant remember names or titles.
There was a king the man and woman were serving. The king, who is, in some degree, possessed and does not know that he's under the influence. This is nearer to the end of the book, and some other guy who I assume wanted the throne, was in control.
The world has a surrounding magical blanket. Only so much energy can be used at one time from the blanket, otherwise it will disrupt life and the whole magic cycle. Yes, this is similar magic to Eragon and such.
A witch is not the evil character but she is spiteful and I believe tries to kill the main female character at some point. There was a tent scene where the female character exerts magic and nearly kills herself before the male character finds her.
The male character gives the female a drug called "Butterfly" something. Its supposedly a poison that is very addictive. She has to take a dose every day or she'll die. During her time living at the castle, she studies poisons. It was her job. She was saved from being hung only because the last poison tester for the king had been killed, and they needed a new protector. She has been in jail for quite some time.
At one time she really does find poison in the king's food and is ill for two days.
The antagonist keeps her in a prison cell like thing and messes with her mind, I guess. She also has a ghost that haunts her, and eventually banishes it.
In the end of the book, her and the male character are stuck in a prison cell, and are hiding and pretending to be dead. They kiss while in there, and make their escape. He and her, if I recall correctly, don't end up together in the end of the story. They go separate ways.
These are out of order random snips of memory and I recall a lot just not names or titles, which is key. I know these don't turn up many results, but I know it was a good book and only just a few minutes ago remembered I read it. Now its driving me crazy.
found the title.
Lol as soon as I started reading your descriptionm I was like "This HAS to be Poison Study" and I got all exceited coz I thought I'd be helping you, and I get to the bottom and you already found what it was called ^_^ Any who the first book is called "Poison Study" then its "Magic Study" then "Fire Study". The series is by Maria V.Snyder. She also has a new series out if you're interested the first is "Glass Storm". Have fun re-reading =)