The Book of Doors by Gareth Brown

 

This started off ... more than a little rough, to be honest: There are a lot of POVs and the novel hops around between them a lot (though that calms down eventually); and the voice is distinctly Brit, which is distinctly off for young American women living in New York, New York (I checked to make sure neither of them was supposed to be Brit, more than once); and there's some weird threat stuff that remains mostly nascent or latent or something for a while. But it gets better--maybe I got used to the voice, but it gradually stopped lighting up all by Brit Prose Sensors; and the threats came together (and tied together kinda nicely in a kinda unintended consequences kind of way at the end); and the characters started to come together as something like people; and the story started to build up momentum about the time it started getting all nonlinear and time-travelly; and there's a grace note at the end that will hit people with different degrees of force but which landed on me kinda like a ton of well-aimed bricks. Very much in the vein/s of Morgenstern's The Starless Sea or maybe Harrow's The Ten Thousand Doors of January, though less meta than the former and less monster-laden than the latter; probably somewhere between them as far as "good" goes, somewhere past the middle in the direction of Morgenstern, I think.