This is the latest installment in the "Laundry" series, but has nothing to do with that agency. Instead, it is exploring a spinoff set of characters, using Stross' latest conceit – adding an overlay from another literary work. In this case, it is Peter Pan, with names and characters drawn from that story.
The biggest problem I had with this book was that there are so many similar new characters who aren't distinguished from each other and who – confusingly – all have nicknames, so that you almost need a chart to keep straight who's talking to who. Further confusing things is that everyone who is in a relationship is in a same-sex relationship, so you can't even use the gender pronouns to identify who is speaking much of the time.
Toward the end it started making a little more sense as the action picked up, and I did enjoy the ending, which resolved a number of open issues. But it took a long time for me to plow through this once because it was simply so dull. But I did just purchase the 11th book, and even though it is using many of the same characters, it is making more sense. This was draws from "Mary Poppins." No, seriously. It's a Lovecraft/Mary Poppins mashup.