What happens when you wake up in the middle of a park, with no memories, surrounded by bodies? If you're Myfanwy (rhymes with Tiffany) Thomas, you find a letter in your pocket written by the person you used to be and take over her life.
The previous Myfanwy was a high-ranking agent in a secret society that protects the world from supernatural dangers. The previous Myfanwy was also a shy clerk, terrified of her own abilities, and unable to ferret out the traitors in her ranks after discovering them through accounting discrepancies. New Myfanwy may not know what's going on, but that's not going to stop her from stepping into her own, unfamiliar shoes to discover the workings of a secret organization and all the other strange people who inhabit it, as well as who tried to have her killed.
This is an excellent blend of genres, and should appeal to those who love urban fantasy as well as those who like mystery and slightly laid-back thrillers.