Nadia used to be a cop, but she got "retired" from the force when she took justice into her own hands and shot and killed a child-rapist. Now she makes her living as an occasional asassin, doing mob hits for a small-time "family". When a serial-killer starts using an MO that make's him look like a professional hitman, Nadia's sometime mentor Jack asks her to join a "squad" of hitmen to take down the guy who's giving them all a bad name.
Like the title of my review says, it's hard to warm to a hired killer. Yes she's got history which makes it somewhat understandble, but nevertheless our heroine is a pretty cold individual on the surface. It speaks volumes of Armstrong's skill that I actually DID warm to her in the end, and will look out for the next book in this series.
Fans of Armstrong's "Women of the Otherworld" series be warned - this is NOT SFF. Definitely worth a look if you're into crime and a strong female protaganist though.