Stray Souls is not necessarily a sequel to Kate Griffin's earlier Midnight Mayor trilogy, but more of an extension into the same dark, wonderful urban fantasy world of London that the Midnight Mayor storyline occurs in. Stray Souls can be read without reading the Midnight Mayor trilogy, but I'm going to make a safe bet that if you like Stray Souls, you're going to wind up reading the Johnathan Swift trilogy anyway, so we're good there.
Stray Souls is for the most part the story of Sharon Li, a young woman of London who hates her job as a barista, is as unsure of where life is taking her as anyone is, oh, and she's a shaman. At least that's what different individuals and thingies keep telling her, and they seem to have an idea of what that means much more than she does, which leads to all sorts of problems. Imagine if Luke Skywalker lived in London and Yoda was a jerk,you get an idea of how the whole shaman business goes for her. Combine her new involuntary career choice with the challenges of handling a support group for Supernatural beings that look to her for guidance she's not particularly sure she can give, and you have the beginnings of a fantastic story. The dangers that come after her and hers, even more fantastic.
Griffin does a wonderful job of continuing the urban mythos she started with the Midnight Mayor, and anyone who enjoyed the previous books of hers, or anyone who likes to see the bar of quality regarding urban fantasy get knocked up a few pegs will not be disappointed. Four stars.