First, there will be spoilers in this review, so beware if you haven't read the book yet. Also, it's a good idea to re-read Year One if you haven't if only to keep the recurring characters straight.
If you're a Nora Roberts fan, you'll still get an enjoyable read - barely. The early part of the book including Fallon's training is interesting and engaging. There is actually some character development, a rarity in the rest of the book.
Despite the promising beginning there are some gaping holes and verbal ticks that are repetitive, annoying, redundant. The end of the last sentence shows what I'm try to say, convey, express. Sometimes this rhetorical trick is used as a shortcut to give the reader a lot of information in a brief sentence; for example, they strip houses that are abandoned, decayed, damaged. See how annoying this gets?
Every writer has their foibles and this one is not new to Roberts.
Where it's definitely not okay is using it to gloss over sloppy plotting and meaningless padding. Does it matter that the characters choose abandoned, decayed and damaged houses to rehab? If it does, show me why and quit droning on like a prissy schoolmarm!
There are some areas that are disturbing as she doesn't discuss but dictates with the barest attempt at seeing the other side. She conflates cultism with pacifism, for example. A second example is the rape of a boy that is mentioned and then ignored for the rest of the book. It would be far better not to include rather than dismiss a devastating life experience without follow up. And it's questionable to have Fallon have to choose her entire life path before she's reached the age of consent. The book says bluntly she chose freely; should anyone just reaching puberty be forced to make a decision of this magnitude?
She also makes poor Mallick eschew female companionship and sleep generations to fulfill his role without much explanation - but her heroine is obviously not likely to follow the same path. Why?
Oddly, she did include a nod to one physical law, the conservation of mass, but she blithely disregards gravity. But the frequent internal inconsistencies are disappointing because this could have been a good book with a modicum of effort.
Another unsatisfying aspect is that her characters use magic that is not explained and that they don't earn. It just "happens" at the right time.
Finally, and most damning to me, her hero Fallon is priggish and humorless. Roberts for some reason endows only strong female magical characters this way (see her other books). Everyone else is allowed to be human.
If you want Nora Roberts at her best with a splash of magic/horror, try her Pagan Stone trilogy. It's a keeper.