I tore into this book right after the first, and it delivered.
A+, extremely solid character development of Vasya and her family. LOVE seeing that her siblings are all very good at what they do -- warrior politics monk or mother and princess holding her family's reputation and fortunes together carefully, both Sasha and Olga were extremely competent, fully rounded humans, and you can a really common thread between the siblings. What is presented as making Vasya special and powerful is also present in her siblings here, even if they are different people who made different choices.
(Also, I loved all the parallels between Olga and their mother. Wonderful.)
I LOVED that everyone's choices have CONSEQUENCES. I love the emphasis on choice -- the mother or the daughter? piotr or vasya? vasya and morozko. vasya and kasyan, etc.
Loved the world building here. This Moscow is a completely different setting than Vasya's forest home, and it's just as richly drawn.
SPEAKING OF KASYAN, I loved him. I love how he echos her initial fiance -- laughing, proud, with something angry. I love how he's fascinated with Vasya because of her spirit, but it's still easy to see that he's broken by his own past. That bit about the tricks and the lies and the passion? Wow, lemme tell you, I loved it, but it was also easy to see why that wouldn't work for Vasya, but also see another path, another Vasya it would work for.
I can't get over how much I love the plotline with Morozko sliding between humanity and immortality, how badly Vasya reacts to the bit with the sapphire in Moscow and how ENTIRELY IN CHARACTER for both of them it was. Delightful. Can absolutely not wait for the next book, it's killing me here.
ALSO, the whole bit where Uncle Vasya takes his niece riding through town? It's wonderful.