The plot line is simple: Our (Anti-)Hero has been assigned to kill Our Heroine. She has a vase that a Whack Job wants for a ceremony prior to Unleashing Terror Upon the World. She also, altho she does not know it, knows where the vase originally came from. Hero is supposed to kill her to prevent Whack Job from getting his mitts on her and getting the vase and the information out of her.
Our (Anti-)Hero is unable to follow through. He tries valiantly, and kills a whole lot of other people in the course of the book (IIRC, all followers of Whack Job) but can never quite bring himself to finish her off. They travel from location to location (her job, her house, her mother's house, her house up on Bainbridge Island, his cousin's place in Tokyo, blah, blah, bleeping, blah, wait, no, that's _Just One of the Guys_. But boy, I sure like that phrase. Never mind.), chased by Teh Bad Guys, ramping up the sexual tension and very carefully divulging as little as possible of the extremely simple plot.
It's clear that this book interconnects through background characters with other novels by the same author. I don't think this is the first and I'm sure it's not the last, but don't ask me for the series details because I don't know them. It works more or less as a standalone novel.
In addition to the deeply troubling theory of psychology and sexuality that underpin the developing relationship between Our (Anti-) Hero and Our Heroine, I had one problem with the book that just made it almost impossible to take it seriously. I got through on narrative thrust (which is saying something -- Stuart can freaking write so if you just want a ride and can turn off key brain cells, go for it). But I just did not understand why The Committee didn't kidnap her, stash her somewhere and explain everything and try to get her to tell them where the vase and/or shrine were. Killing her struck me as pointless, crude and unhelpful as a solution, especially since that was about as far as they were prepared to go in terms of offing bystanders -- they changed their tune once Our Heroine's younger sister is grabbed.
But hey. It's a trashy novel. If it's your kind of trashy novel, I wish you all the best; it looks like Stuart is having no trouble selling these so you should be supplied with the good stuff for a while.