Mary Finch has travelled to London to peruse certain papers pertaining to the history of White Ladies, but instead she finds herself face to face once again with Cuthbert Shy.  He wants her to go on another mission, this time across the Channel to dangerous post-Terror France.  She must pose as the wife of an American artist, a man who already has a wife waiting for him in Paris.  Meanwhile, Captain Holland is on the trail of a mysterious "sea monster."

If you like fast-paced adventure stories you might be advised to give this one a miss, as the pace is fairly ponderous.  However, if you want to read about the reality of this type of work, which involves much waiting and surveillance, then this certainly fits the bill.  There are some genuinely nail-biting moments towards the end of this book as well as a fascinating look at what France must have been like at this time.  Normally, historical novels tend to deal with either the Revolution or the Terror due to their exciting, larger-than-life events, but this novel looks at the quieter, though still worrying, time that came after.

Mary and her companions deal with hellish bureaucracy, sinister agents and strange scientists, while viewing the surroundings with remarkably observant eyes.  We see a time when the Revolutionary calendar is still used by many, there are priests but churches are still officially unpopular and everywhere there is devastation.  All of this tends to almost make up for the slow pace and Mary’s oddly charmless beau Captain Holland, but I was still left with the feeling that some editing would have been a great idea.  This continues to be an unusual series that is worth reading for the descriptive powers of the author that allow the reader to take a peek back into the past.