I read this shortly after reading Mirror Mirror, also by Maguire. I detested Mirror Mirror, so by comparison, Hiddensee was much better. After some thought and discussion with someone else who had just read it, I realized I didn't really like Hiddensee all that much either, I just liked it more than Mirror Mirror. First note: whoever decided to tack on 'A Tale of the Once and Future Nutcracker' needs to go sit in a corner and think about the wrongs they've done. This book was not a Nutcracker retelling. Not even close. This book is the story of Dirk Drosselmeier, Klara's eventual godfather who gifts her the Nutcracker. Beware, spoilers abound.

We'll start with the negatives so we can end on a positive.
All of the potentially interesting elements were left completely undeveloped and unresolved.
• We had the bit about the magical forest set adrift with Pan and Pythia on board. In fact, the story opens with Dirk ending up there and meeting them and getting kicked out for cutting down one of the trees. It seemed to me like he was supposed to earn his way back in during his life, but instead he forgets all about it and walks around with the Pan knife and nothing comes of it.
• Also the Pan knife--a big deal is made about "don't pull it out of the dirt, don't release him," Dirk does anyway and then nothing really happens.
• We get a glimpse of one of the Brothers Grimm and Dirk's adoptive parents turn out to be Hansel and Gretel, but nothing is done with those elements besides the name-drop.
• The Nutcracker story is squeezed in at the very end, taking up very few pages and all we get about the great battle with the Mouse King is a passing mention, all of a few sentences. The nutcracker itself, the actual object he creates, is mentioned a few times and is reduced to an object no one wants, until Dirk gives it to Klara.

Dirk himself is "mysterious," not because there are mysteries he isn't revealing about himself or because there is anything particularly intriguing about him, but because he's this blank canvas of a person. He has no past because he's a foundling and he doesn't know or remember much about the people who raised him. He's by-and-large completely disinterested in everyone and everything around him, other than his infatuation with his employer's wife (whose name I can't remember) and Klara, who seems to be the one person in his entire life he ever cares about. He has no passion for anything and is flat and empty because of it.

I think my biggest problem with Maguire in this and Mirror Mirror is the wasted opportunity. In both cases, he comes up with some great elements to play with and incorporate but he wastes them. His main characters are empty of anything that would make them remotely interesting and his plots meander about pointlessly.

Now for the positive.
It was a short, fairly quick read, coming in at less than 300 pages. There were some interesting elements, though undeveloped and seemingly forgotten about, that grab your interest and leave you hoping for a pay off. And the cover is beautiful.

Despite an interesting concept, potentially interesting characters, and a beautiful cover, this story ultimately fell flat.

The first half of the book was pretty slow, establishing the 4 characters this story is told through. Once I got through that, the story did pick up, with characters starting to interact and connect. Unfortunately, I was left largely unmoved by the outcome of these interactions. If handled differently, certain story beats would have had me on the edge of my seat, but instead the tension just wasn't there and I moved through the story to the end and was left with a sing thought: that was it?

Spoilers ahead...

I think I've narrowed down the elements that have left me feeling rather dissatisfied with the story.
1. Fill. What was the point of having him as a POV character? He served 2 purposes in the story, to give the breaks to Soq and to bring Barron and Martin Podlove together, culminating in Fill's death and setting off the 'war'. His fascination with The City Without a Map, the guilt over his grandfather's past, the things that make him an actual character, aren't explored or brought to any sort of satisfactory ending. He just dies in a ball of fire and the story moves on.
2. The breaks. Talked about endlessly throughout the book. POV characters even express an interest in trying to find out where it came from, how to cure it. But ultimately it gets a shrug. We don't really know what it is, where it came from, but for 'reasons' nanobonding fixes people so they don't die from it so whatever.