I've read and mostly liked the previous novels in the Rizzoli/Isles series - some more than others. This is competently executed crime fiction, with both police procedural and thriller elements. The forensic aspect of the series - represented by the character of Dr Maura Isles - plays less of a part in this novel. This was a plus for me, because I'm rather tired of detailed autopsy descriptions. I am also rather tired of Dr Isles' tortured and soap opera-y love life. Jane Rizzoli is an interesting character, but not as interesting as she could be in this novel. Other characters are sketched in fairly lightly. It's fair to say that there's not a great deal of character development.
The Chinese mythology element in the novel is quite well done and gives an interesting twist to the plot. However, the plot itself is not without its problems. For example, some elements of the resolution are less than believably explained. Just how did the perpetrators start their killing spree?? . However, readers who have major issues with implausibilty should probably find some other genre to read. In my view, the ability to suspend disbelief is a required skill for a reader of crime fiction.
The novel is set in Boston. I guess some Boston locations are mentioned, but the scene-setting made little impression on me. I don't get a strong sense of place from Gerritsen, in the way I do from Denis Lehane (who also sets his novels in Boston), George Pelicanos (Washington) or Karin Slaughter (Atlanta for her most recent novels).
It feels like I am damning this novel with faint praise. That's a bit unfair, because I did like it. I just didn't love it. That said, when the next novel in the series is published, I will almost certainly read it.