I really enjoyed this one. It's my first by this author, but I'm certainly interested to read more.
This is a very quiet story and a very slow build. Martin is highly shielded and Arthur is socially awkward. They're both considered weird by their coworkers and Arthur tries to find out if they're weird compliments each other.
The cover made me think this was going to be historical Brit fic rather than contemporary American, so that took a couple of chapters to adjust to. I did like the quiet tone of the book and how Martin and Arthur's relationship developed. It's difficult enough to show relationship development when the characters are talkers, even more difficult when they're not, yet somehow this author manages it. The small gestures, the show of trust and caring - it's all convincing. I was especially surprised and pleased when both MCs were revealed to be asexual and this didn't become a "fix the ace" travesty. (So those who want sex in your books, you're not going to get it here.)
There are a lot of unanswered questions, which is a given considering their jobs, and I'm ok with those. I would've liked to get to know more about Martin's backstory, but he doesn't really start to open up until the very end. The hints we get are intriguing though and opens the room for a lot of reader speculation, which in a way is more fun than getting it all spelled out for you. (Still, if ever there was a book that needs an epilogue, this is it.) There's some handwaving that needs to be done in regards to the Agency and how it appears to operate, but it didn't detract from the tension or suspense in the last quarter of the book at all. It was actually used to some great effect.
There were a few more typos than I would overlook normally, things like verb tense changes and at one point even character names get mixed up, and general typos that wouldn't get caught by spellcheck but should've been caught by an editor.