Update:
I finally got a chance to listen to the audiobook, which was a lot more emotional than I'd realized it would be. Mary Robinette Kowal's voice breaks when Toby's voice would break, and ... it's a lot. I mean, it's amazing, but it's also not something I'll be up for every day. On re-reading, I acknowledge this isn't my favorite in the series, but it's a strong addition. A note for audiobook readers: you don't get the bonus story afterward, the way you would if you read any other version of the book. That's ... probably something contractual, and it's honestly a bit of a bummer.

Original review:
I received an advance readers copy of this book from NetGalley in exchange for an honest review, and I'm going to keep it as spoiler-free as possible, while still making an effort to do the book some small amount of justice.

First off, a note to would-be readers: Make time to read "Of Things Unknown," the short story at the end of The Brightest Fell, sometime before you pick this up. It isn't as if the whole plot of this book hinges on it or anything, but you will at least save yourself a few moments' confusion. (This is the first time I can think of that a short story felt necessary, to fully follow a book in this series.)

Now, to review...

This is a solid addition to the series, continuing the ongoing theme of facing consequences and reconciling with one's past. Seanan doesn't pull many punches, and we see the trauma left over after Amandine's bad behavior playing out, even as the characters face the crises that make up the bulk of the book. For once, Toby's not the most broken character, which takes a little getting used to.

Tone-wise, it's a little less fun and quippy than some of the previous books, but it's still enjoyable: we get to reconnect with a nice subset of both our favorite and our most hated characters. We get to meet at least one new and horrifying type of fae, which is always great. We get at least one big question answered and several new ones asked.

Solid. A+. And enhanced ever so much by the novella at the end of the book.