Like the previous story (Deceiver) the description on the back of the book refers more to the previous novel than to this one.
'Deceiver' ended with Ilisidi sending Bren Cameron to talk to a hostile lord, Machigi. 'Bertrayer' opens the following morning, with Bren about to have an interview with Machigi, who, it turns out, is not responsible for many of the hostile actions laid at his door. To prove his good faith, Machigi returns the accidentally kidnapped Barb as well as Veijico, the young Guild member who had followed Cajieri's orders a little too literally.
Cajieri is growing up fast and in helping Bren's injured brother, Toby, learns a great deal of what is going on and does not, for once, act rashly.
This story ends the 'mopping-up' actions which followed the Civil War and does make for a satisfying conclusion, as we finally learn exactly who has done what to whom - and who will suffer for it!
If you have never read one of the 'Foreigner' stories before, I wouldn't recommend starting with this one, as it follows the action in 'Deceiver' so closely - try 'Conspiritor' instead, as this is the first of the three in this series.
Hopefully 'Intruder', the start of the next trilogy, will deal with a visitation of the Kyo - wouldn't it be great if their 'hostile neighbours' turned out to be the Hani ???