I finished the book last night and I really liked it, so much that I ordered the first three in the series from my local library. I like how Rei is conscious of looking older (at just 30!!) , and grows to accept it. The last line of the book is "...and because I finally understood that my own winter years were nothing to be afraid of."
This is not, however, the focus of the book-Rei has been barred from entering Japan because of an earlier incident, and she is offered a job by the government to go to Japan legally and find out if her former lover is actually in possession of a priceless treasure that was looted from a museum in Iraq after the fall of Saddam's government. In the process, she becomes embroiled in a mysterious death and in her quest to find out the truth, she uncovers both the whereabouts of the priceless object and the answer to the mysterious death, at some peril to herself. This opens the way for further government jobs, although her job description falls short of "agent".
The book is fast-paced and well written, and kept me turning pages, which is sadly unusual for me these days. I am glad I found a series that piques my interest.