This book could have been a much-needed, and appreciated, queer fairytale. Instead, it took two steps backwards for each step forward. Spoilers below.

1) Pro - A non-binary hero stumbles into a journey of redemption, self-discovery and true love.
Con - Said character is introduced as a trans person, who uses their assumed identity to mislead and harm their love interest. The world did not need more Trans People Are Secretly Trying To Hurt You characters in fiction.

2) Pro - A resilient and cynical black heroine - whom society has cast down - learns to trust in herself and others, and unlocks a power and happiness she hitherto thought inaccessible to her.
Con - A black person is society's punching bag, so she turns to a life of crime. We didn't need more All Black People Are Criminals tropes in fiction.

3) Pro - A heroine living a confused, harried life, comes to realize that she is more than what society expects her to be, and she has access to literal magic when she is true to herself.
Con - Magical Black/Asian Girl trope. Too often in fiction, people of color or islanders get romanticized as having access to mystical wisdom/magical powers. Romanticizing Otherness widens the gulf of understanding between races and contributes to racism. Would have been nice if either heroine were powerful because of their personality traits (kindness, courage, etc.), or because of their chemistry together, rather than witchcraft.

4) Pro - A queer fairytale has two heroines explore genderized roles - male and female - in order to fit into society, before rejecting society entirely and becoming something completely, profoundly new, and Right for them.
Con - Spoiler: They become fish. Well, they become mermaids, but mermaids in this universe are very fishy, having wide-set eyes and gills on their cheeks. Again, we have a widening chasm instead of a bridge, representing queer people as Other, even Non-Human.

Getting off my social justice soapbox, this book's technical writing was also problematic and immature. The author repeated themselves, seemingly for emphasis, but often unnecessarily/to little effect. The switching point-of-view characters didn't work for me, there was no suspense left to the book, and also I was confused as to whether the author wanted us to sympathize with the viewpoint character or not. There were plotholes (like why blow up a ship when A) You're on it, and B) You're supposed to be conducting a stealthy rescue mission?). The characters largely don't have character arcs: Evelyn is already kind and unconventional, Flora is already aware of their gender fluidity and /moral/ fluidity, Rake knows he is silent and complicit and never pays for it, Genevieve is a loyalist who remains loyal despite learning of her government's many corruptions... The only measurable growth is minor: Flora, who knows she is comfortable as Florian... admits that she is comfortable as Flora or Florian. Which is great and all /for Flora/, but does nothing for the people she's murdered.

All in all, I felt this book was trying to do something profound, but failing in its task. I vacillated between being angry and being bored.