Oh dear, second novel syndrome strikes again. After Charlie Jane Anders' misstep this is another. It wasn't quite as bad as that one, it is still well written with some good ideas and a tech in-joke about time travel that brought a smile. However, it has serious issues.
Firstly, it's a time travel story. I am not usually a fan but I gave this a shot on the strength of the author's debut. This book (for me) fell into the common trap of time travel novels in that it fetishised certain periods without reflecting the reality of that time fully. As a result of this fetishisation there are pacing issues, it wraps up far too quickly because the author spent too much time dithering about in her favourite time periods.
There is also an unreliable narrator identity switch which I felt was entirely unnecessary and actively detracted from the story.
That being said, it was written well enough and I did finish. I just don't feel it was strong enough to recommend.