Well, that was an insufferably boring 600 pages of nothing happening.

Considering the title (subtext!) and the obvious (superficial) similarities to Riverside, I was hyped for this to be the gayest book. Unfortunately Clare has stuck with her usual modus operandi of establishing the two main male characters as having a very close bond, and then immediately sticking a woman in the middle. Writing stories about male friendships is a cool and good thing to do! But CC has been writing about men in life-long partnerships for twenty years, but she has never once just let it be gay, and this time I was hoping for a different flavour, or at least a deep exploration of the concept, which the book doesn't deliver on.

I see all the comparisons to The Shades of Magic, which are certainly worth talking about, but I wouldn't go so far as to call this 'plagiarism' just because CC has undeniably borrowed a character name and basic concept as a starting point, and it's not as if Schwab was the first author to have the idea of a 'layered' city, either.
As the first book in a trilogy, in comparison to A Darker Shade of Magic, by my reckoning Sword Catcher comes out quite far ahead, because the prince actually exists as a character in this one (he's not a terribly interesting or likeable character, but he is at least present in the story, which is more than can be said for Rhy), and as weak as the worldbuilding is here, CC has at least made more of an attempt at giving her world a history than Schwab, who had one good idea for a setting but failed to develop it at all beyond the most basic aesthetic.
CC takes about as much inspiration from Shades of Magic as she does from ASoIaF, Riverside, Six of Crows, and probably other things I'm not familiar with. What is worth complaining about is that her obnoxious habit of lifting 'funny' quotes from TV and movies and putting them in the mouths of her characters is still alive and well. The first time I got close to throwing the book was within the first couple of chapters, when one of the characters makes the 'tracts of land' joke from Monty Python and the Holy Grail.

As is usual for YA authors attempting to transition into adult (Roshani Chokshi, Hannah Whitten, Leigh Bardugo etc al), this reads almost exactly the same as a typical YA novel in terms of its prose, plot beats, and character dynamics, but the pacing is (painfully) slower, the characters are slightly older and there are more mentions of sex and swears (although surprisingly little sex is actually accomplished, with the 'steamiest' scene being a flashback/dream vision about historical figures).

Speaking of which, what the fuck was the love...polygon in this book? The marketing is selling us 'forbidden love', but it's unclear which pairing it's referring to - every pairing is 'forbidden' in some way (Kel's secret identity as the prince's body-double precludes any romance for him; Prince Conor can't pursue Lin because she's Jewish Ashkar; a lot of boring politics gets in the way of either man romancing Antonetta), but all of these half-formed attractions are happening at once, as the characters are being switched around between different combinations, with the result that no two characters have enough scenes together to build a romance with enough emotional depth to be worth caring about. In a novel that purports to be 'adult', it's bizarre how none of these adult characters ever consciously recognise or consider that they could be 'in love with' or even 'attracted to' someone - such things are always couched in vague language about 'feelings they can't identify'.

Kel fancies his childhood friend Antonetta, who doesn't get a POV but seems to have some kind of feelings for both Kel and Prince Conor (and Kel when he's impersonating Conor), but Kel also has fond memories of the prostitute Silla (a character who serves no purpose other than to be a prop for virtue-signalling about sex work being real work, in a strange subplot about

a rape victim who girlbosses her way into becoming the madam of a brothel),

who also sleeps with Conor, who catches an instalove/hate attraction to Lin (because they are

the reincarnations of fantasy King Solomon and the Queen of Sheba???).

This plot where the 'reincarnation' of the deified historical figures are revealed to be one of the main characters is shockingly similar to Hannah Whitten's Foxglove King, though I assume this must be coincidence as both books were probably written concurrently. In any case, the historical story being told through the chapter epigraphs is far and away more interesting than the main plot happening in the present.

The worldbuilding is paper-thin and the setting (an ersatz Renaissance-era Venice which seems to be an homage to Ellen Kushner's vastly superior Riverside) extends exactly as far as the immediate needs of the plot require, and no farther. Certain proper nouns are barely altered from the real-world equivalents (Ashkenazi --> Ashkar), which is probably intended to lend the story some historical gravitas, but really just comes off as shallow and lazy.

The prose is serviceable but nothing special, but Clare treats the reader like a fool - she constantly indulges in an absolutely infuriating and immersion-destroying habit of using a literary device, and then immediately afterwards having the POV character's internal monologue tell the audience about the use of the device, just to make absolutely certain we didn't miss what a clever author she is (e.g. in an early chapter, the prince injures his hand; later, Kel injures his hand, and he is sure to tell us how spooky it is that they've suffered the same injury. Gosh you guys, it's almost like the blurred line  between their identities has become physically manifest through a parallel scene!).

The story is firmly in bildungsroman territory (Kel spends a lot of words angsting about the lost halcyon days of playing pirates with his childhood friends; Lin has her first attractions and kisses), but this is a rare (pseudo-)YA novel which is at least attempting to have a theme beyond the generic hero's journey tropes about 'finding your inner power' and rebelling against evil invaders/governments/religions/whatever. The theme is the nature of personal identity, and the narrative seems to be interested in exploring the tension between self-perception and the perception of others, and the ways that identity can be suppressed, subsumed, compromised, replaced, transformed (Kel is an orphan of completely unknown provenance, who is raised in the palace as the prince's cousin and secret body-double; the ruler of the criminal underworld is the mysterious Ragpicker King, which turns out to be a title that is passed down between men who forsake their former identities; at the end of the novel

Lin publicly declares herself to be the reincarnation of the Goddess, to give hope to a terminally ill friend - although presented as a conscious deception, her agency in this declaration is undermined by the fact that she has gained magical powers from an artifact of the goddess, and has been experiencing flashbacks of the goddess' past life, so all signs indicate that she <i>is</i> the reincarnation, but not bright enough to figure it out).

Unfortunately this book only serves to introduce the characters, plot and setting, with no 'pay-offs' to speak of, so nothing interesting is said about this theme; for now, it merely exists.

By far the best character in the whole thing was the big-sisterly bodyguard of the French fantasy-French princess,

but she was far too cool to live.