This is a very clean romance. There are no OW or OM. There is no rape or sexual assault of any kind. There are a few murders (one at the very beginning) and a few in the last quarter of the book. They are not graphic. There is a little assault, but it ends abruptly. There is no theft, PTSD, burning, or anything else, really. The main characters can't even touch each other until the VERY end of the book, and even then, they only kiss. There is a "sex scene" in the epilogue, but even that wasn't graphic at all. This can easily be read by teens and would probably bore the daylights out of them.
This story was very bland. There was no action, suspense, drama, comedy...anything. For almost the first half of the book, the MMC was actually kind of a jerk to the FMC, and she still was swooning over him. It actually didn't make any sense. It was insta-lust on her part, and she was fawning over him even though he kept telling her off. Then, at the halfway mark, he all of a sudden was head over heels and confessing his undying love. It was too easy and quick. There was no work or reward for anything. Understandable, I guess, since it was the first woman he'd seen in 700 years. Understandable but not enjoyable.
Think about what makes a really good fantasy book. The world, the magic, the characters- sure, the plot matters, but if you don't feel like you're in the make-believe world, then the whole thing falls through. Since this is a historical book, it needs to FEEL like the historical parts are believable, and they just weren't. She was supposed to be an archaeologist, and she barely did anything. They were supposed to be knights, but all they did was joust. She was supposed to be in England but the accents kept sounding Scottish. The guys have been dead for 700 years but there is no backstory about that at all. You never hear what it was like for them to watch time fly by or how people reacted to them being ghosts or what they did to pass the time, or anything. Just the whole thing felt like a whim instead of a well-thought-out plan.
The plot was flimsy at best and didn't go anywhere. It was so blaringly obvious and not in a "hey the author left great bread crumbs" but in a "can you please hurry up and go ___ because there's no story here." but it takes forever for anything to happen and then the FMC has the gall to be shocked when it does. Sigh. I bought a three pack of this author's books at a used bookstore but I'll probably toss the other two.
I recommend this book for people who like calm, clean reads with no stakes involved.