Trigger warning for non-con/dub-con.
Upfront: I've never read any of the King Arthur legends. I watched that one Sean Connery and Richard Gere movie and found it trite. I made a couple of half-hearted attempts to watch "Merlin" and lost interest. Not that these aren't my kind of stories. I love a good fantasy tale. But King Arthur and the Knights of the Round Table just never called to me, for whatever reason. The only reason I got this book was because of all the one-star reviews gay-bashing it. So I'm giving this a neutral three-star review only because I know I can't really be unbiased, having no interest in the subject matter going into it, and a lot of the things I found to be confusing were largely due to my ignorance of the legends.
The story takes place after what I assume are the events of the actual tales as told in ye olde tymes. Lancelot has been stripped of his knighthood and banished from Camelot, and all of England. (Is Arthur actually the king of all of England? I thought "England" was actually still a bunch of serfdoms back in this time and not a country in its own right. See above re: confused.) After his banishment, Lancelot sails off to... I don't know where, but they speak English there too. :) He meets a young boy in trouble and saves him, and they travel together for awhile. But Lancelot's new squire isn't all he appears to be, and soon there are extremely mean fairies getting up in Lancelot's business. Like, ALL of his business. :/
Non-con is big in this book. It touches pretty much every character in one way or another, be it sexual or otherwise. Mostly, it's sexual. I didn't stop reading though, since I felt the non-con was handled pretty well. It's actually openly acknowledged as non-con by all the characters, and there's no attempt at rape-apology or any of that nonsense, or at least none that I've noticed. The fey who use this spell are rightly cast in a negative light for their attempts to use this form of magic to get what they want. The one niggle I do have about it is that Else's experiences in this are not as well explored as Lancelot's. They aren't ignored though, and this is Lancelot's story, so it's only a minor niggle. Others more sensitive to the subject matter may want to proceed with caution.
Overall, I liked the story well enough, though not enough to continue with the series. It doesn't end on a cliffhanger, though there is still obviously plenty of story to come. The characters are all well-developed, there're some really cool action scenes, just enough mystery to keep the pages turning, and plenty of man-angst as Lancelot comes to terms with his feelings for Arthur and what they really mean. There were some distracting grammatical errors throughout the book: commas go missing from one place to inexplicably show up somewhere else they're not needed, incomplete sentences in places they'd be better off tacked onto the ends of the sentences preceding them, dialogue ending in action sentences rather than the correct he said/she said, strangely misused words or terms (such as drips and drabs, instead of dribs and drabs). I would suggest an editor, or even a fresh pair of eyes, to beta read this and clean it up.