After finishing the first book in the series, I moved straight into book 2. Book 1 ends on a bit of a cliff-hanger, so I would've been annoyed if I hadn't been able to continue with the series right away.
This book involves time-walking.
My daughter hates books about time travel. The theoretical issues with the time slip are too much for her to absorb so she refuses to read them. I'm not opposed to time travel, but there are always problem created with a time slip, and this story is subject to many of them (like they have to swear everyone who comes into contact with them to secrecy about the fact that Matthew has fallen in love with a witch 400 years later. Ummm, right. Queen Fucking Elizabeth isn't going to notice that one of her courtiers was married, but then he wasn't married, what?).
But, that's fine. It's the pace that is the real problem. Matthew & Diana manage to timewalk themselves into the sixteenth century, which is slightly problematic since Diana has almost no control over her magic. What is even more problematic, of course, is that she needs a spell that she cannot do to get them back. Sort of like travelling somewhere unappealing (modern India, with its rape culture, perhaps) without the money to get you home. So, you're stuck there, in a place that you don't really want to be, where you are likely to get raped or burned at the stake, until you manage to gin up a method to get home. This is not bright.
Once we get to the sixteenth century, well, there's witch hunting, and name dropping, and burnings at the stake and Matthew gets to spend time with his dead father. It all gets dizzying. It is an entertaining romp through history, for readers who are into history. If you're not into history, well, I definitely don't recommend this book.
I ended up enjoying it just enough to read the last book in the series, although it has been slowly collapsing into a mess. Can Harkness pull the series back from the brink of incoherence? Time will tell.