Okay, I'd to start by saying this sounds absolutely AMAZING. Like, really, really good, and I'm not even that big of a fan of Arthurian tales. And with that, my line edits:
Self-absorbed King Arthur isn't Gwen Masterson's only problem. Someone is out to kill her.
I don't think this is really necessary -- it sounds cliched.Orphaned at seventeen following the death of her father,
she Gwen Masterson'sand her younger brother Leigh are sent to live with an uncle in the middle of nowhere. Iowa farm life is a far cry from the city-suburbia
choose either city or suburbia of New York, but Gwen is determined to make the best of the situation. Things take a turn for the strange when Gwen discovers a book in her uncle's study that, when read, sends her back in time… to Camelot.
Gwen's days are spent in the real world
. Her nights, however, while her nights are a whirlwind fantasy in beautiful Camelot. It's a dream come true for bookish Gwen until she learns she's nothing more than a pawn in Merlin's schemes and is now trapped in Camelot.
I like how this line is worded. It gives us some good insight into Gwen;s character 
The plan is simple: find a strong woman to become Arthur's wife and change the legend
I would put WHY changing the legend is important and why a strong woman is needed to change it. Unfortunately
(I would specify that this is unfortunate for Merlin, because at first I thought you were referring to Gwen, which confused me), Arthur treats the headstrong Gwen like any other female of the time: beneath his notice -- and Gwen wants nothing to do with the arrogant boy king.
(New paragraph) ==> ButArthur isn’t Gwen's only problem. The eccentric man Gwen believes to be her uncle is hiding a secret
andMorgana
now has Gwen on her 'top people to kill' list thanks to Merlin's meddling. When Leigh finds the book and attempts to rescue Gwen from Camelot and her upcoming marriage
I thought that Arthur didn't notice her and that she didn't like him?), he becomes Morgana's prisoner instead. Gwen's agenda is growing by the day with no end in sight and time is running out.
Alone in Camelot, Gwen has to rescue her brother and find her way back home – without falling prey to Morgana. This may be Arthur's opportunity for a second chance, but Gwen doesn't have the luxury of a do-over if she fails. Facing the choice between running away from Arthur or following a new destiny, Gwen is caught in the crossfire in a battle to change the course of history.
I don't really think this last para. is necessary, but of course that's subjective. I think that query is done after the line about her agenda: The stakes, the plot, etc. are all there. CAMELOT FOUND is a YA Fantasy novel with romantic elements and is complete at 76,000 words. It is the first installment in an intended trilogy, with the main storyline taking place between the modern and medieval worlds. It will appeal to fans of Arthurian literature, the BBC show Merlin
I think that all titles are in caps. I had a movie reference in my query and used all caps in the titleand those who have ever wanted an escape but never anticipated the repercussions.
Okay, so I have a lot of extra questions and you don't necessarily have to incorporate all of them. I think that this is a good query that could be shortened some and that other things could be clarified. All in all, this story sounds AWESOME.