This book takes place in the "Honorverse", the world of Honor Harrington, but Lady Harrington only has a cameo appearance. The story itself stands alone fairly well, and the universe would probably make sense without already being familiar.
This book has so much wrong with it that I'd have plenty of meat for a very detailed pan. It's 745 pages, which is certainly a couple hundred too many. A lot of what happens is political, and it's convoluted and contrived. A lot of it is military, and those parts include many passages of excruciating description, explicitly listing details. A number of details at many levels seem to be a bit off. Mostly, the first several chapters just dragged to the point where I remembered that when this book had first come in, I'd set it aside unread, and I was thinking that I should have stuck with my decision at the time.
But somewhere, maybe a third of the way in, Weber's magic kicked in, and I became deeply engrossed in spite of all the flaws. I complained a lot more than in the early Honor books, but I definitely had that feeling of addiction.
If you've never tried Weber, this isn't the best book to start with. (Go find a copy of On Basilisk Station.) If space navy battles aren't your thing, don't bother. But if you're hooked on Honor Harrington and haven't been able to get your fix, this does have the same feel. 7 out of 10.
**** PLOT SUMMARY -- MASSIVE SPOILERS ****
This is a long, complicated book, and I know I'm gong to leave out a lot, but I'll try to get a good chunk of it.
While there are lots of battles, the overall story is much more political than military. Things are going badly in the ongoing war with Haven, but that's not what this book is about. This book is about a large stellar backwater called the Talbott Cluster, where dozens of systems are struggling in poverty and suffering interstellar colonial exploitation when they're not being totally ignored. A new wormhole connection has been discovered from Lynx in the Cluster to the Manticore junction. The Solarian League, manifested through the Office of Frontier Security, are brutal colonial masters, and Bernardus Van Dort has been working for decades on a scheme to try to keep the OFS wolves off of his own home world Rembrandt by setting up a trading empire, the Rembrandt Trade Union, that is just about as economically vicious as the Sollies themselves when the new wormhole is discovered. But while most of the rest of the RTU are stereotypical capitalist bastards, Van Dort is actually a good guy at heart, and he comes up with the somewhat hare-brained scheme that he can protect the Talbott Cluster by having the Star Kingdom of Manticore annex them. And he manages to organize and run through a plebiscite, which passes by a solid margin on all the worlds. A Constitutional Convention is organized to agree on a formal collective constitution for the independent worlds of the Cluster and spell out the details of the annexation. Of course, there are some people who don't think it's a good idea. Some of the ruling oligarchs want to force the Convention to include enough "local autonomy" that they won't lose their own cushy positions by having their citizens inconveniently granted status as Manticoran subjects. And a couple of the individual planets have local opposition figures who are trying to fight with force rather than smoke-filled room maneuvers. Much of the book deals with the batshit crazy terrorist Agnes Nordbrandt on Kornati and how much trouble she manages to cause, and the deeply principled but slightly off his nut freedom fighter Steven Westman on Montana. Both of these resistance movements have their effectiveness multiplied by a foreign agent provocateur who is ultimately working for Manpower, through a conspiracy that includes the local (even more corrupt than most) OFS satrap.
On a personal level, we see all of this through the actions of the HMS Hexapuma, a newly commissioned heavy cruiser. Her captain, Aivars Terekhov, was almost the sole survivor of a major defeat decades ago at the hands of the Peeps, and much of the story revolves around whether he's really gotten his demons under control. Other major characters are Abigail Hearns, the only Grayson woman to date to graduate from Saganami Island, and Helen Zilwicki, from Crown of Slaves, now a newly minted midshipwoman.
The first major action comes when the Nasty Kitty, as her middies affectionately name her, discover a couple of pirates while showing the flag in one of the backwater systems. The pirates turn out to be a couple of escaped State Security ships from Saint-Just's People's Republic of Haven. Terekhov proves that he's an effective tactician when he destroys the two warships and manages to recapture the freighter they've taken as a prize. Helen learns that Paul, one of the other middies that she took an instant dislike to because he was so standoffish, is actually a freed genetic slave, not the recipient of hugely expensive biosculpt, and they start to actually form a relationship as they deal with the reality of having killed people in battle.
At this point, the action starts to get pretty furious. Nasty Kitty is sent back and forth in a rather comical fashion between Kornati and Montana as first one and then the other terrorist becomes the greater threat, but as they go back and forth, they manage to first disrupt and then actually unmask the agent provocateur. In doing this, they manage to neutralize Nordbrandt and make Westman realize the error of his ways, but they've also found the biggest threat. Manpower has arranged to arm Monica, a nearby system not considered part of the Cluster, with 14 only slightly obsolete Solly battlecruisers. Through a combination of brilliant tactics and iron-hard resolve, Terekhov manages to destroy all but two of the battlecruisers and hold off the rest of Monica until the cavalry arrives and he can return home with the remnants of his fleet. Hexapuma was heavily damaged but will fight again. The promising pilot, Raghnild Pavletic, is killed, but the rest of the protagonists survive. Just how adding all these worlds to the Star Kingdom is going to work out is left for future books, along with the questions of when Manticore is going to get around to actually ridding the galaxy of Mesa and whether the Sollies are really going to acquiesce to the new arrangement on their frontiers, and whether Helen and Paul will manage to get in bed where they belong.