This novel is set between TFF and TUC, and offers a return of Lenore Karidian - who we know as Kodos' insane daughter who tried to exterminate all the survivors of the Tarsus massacre and ended up killing her own father back in The Conscience of the King.
The plot is quite simple: The Enterprise is sent to host negotiations between two neighbouring planets under the lead of Ambassador Kevin Riley. While visiting one of the planets, Kirk finds an apparently rehabilitated Lenore Karidian amongst a group of relief workers and invites her onto the Enterprise for a gala dinner. Riley's understandably less than amused. After the dinner the leader of one diplomatic group is killed, later another - and the main suspect soon is Lenore whom both planets want extradited. Meanwhile, Spock and Scotty are on one planet supervising the dismantlement of weapons of mass destruction. They get caught in riots because of the assassinations on Enterprise, and find out that one of those weapons that should be destroyed has vanished.
I have to admit that I was looking forward to this novel because of the Tarsus-aspect - but I found myself disappointed by it in the end. Lenore is rehabilited and on some psychiatric drug to keep her in balance, a drug, that is found to be murder weapon in one of the assassinations. It's an interesting aspect, trying to judge whether she's really one of the guys now, or she's still a psychopath. But most of her dialogues devolve into some random Shakespeare quotes (which is a bit tiresome, especially knowing that one of the next psychopaths the Enterprise has to stop also keeps quoting Shakespeare...), which disturbs the flow quite a bit - even knowing that the young Lenore shared the same propensity. Then it's clear from the start that she isn't the culprit - the only thing that was missing was her actually sacrificing herself at the end to redeem herself. Well, she managed to escape the first thing, but either way she redeemed herself. That's way too simple a plotline for me.
I appreciated Riley's reticence (BTW, what a coincidence to have him on board, just as Lenore pops up) - quite as much as I disliked Kirk's flirting/getting to know Lenore, whatever you want to call it. Of course, back then, Kirk used his womanizing ways to get closer to her father... but it's 20 years later. Much has happened since, and practically picking up where he left off seemed wrong, especially since I couldn't detect any sort of chemistry in the characterinteraction here. Getting to know her, talking to her, would have been good and well, it's the "and more"-part I have troubles with.
The same applies to the negotiations/assassinations. I had some idea that both adjutants together planned and executed the murders - especially after Chekov started his allergic rhinitis... Who/what else should he be suddenly allergic to but someone/thing that hasn't been on Enterprise for long? That's quite a broad hint. Cox manages to (re)introduce a couple of plot-devices during the investigations, such as that locating-patch that saved Kirk and McCoy in TUC, and of course, the transporter-accident that, for a short time, split Kirk in 2 (The Enemy Within). That was nicely done. But in other respects I really had to wonder. For example: We are meant to believe that a ship like the Enterprise only has 2 shuttles? And why not make use of the second shuttle on board (the first is with Spock/Scotty) to try and intercept the warhead - the idea only comes up when Lenore uses it to try to give herself up to one of the planets in order to save the peace process? Or, why can't the transporters be used to locate the perpetrator - granted, it might not be wise to transport within the ship, but the perpetrator already did so, and given the danger, wouldn't it be worth the risk to capture him/her as soon as possible? And it's not as though there had been any other member of his/her species on board, so the computer should have had no trouble locating that person.
Overall, while the premise is sound, its execution is lacking in complexity and ingenuity. The plot is too straightforward, contains hardly any surprises (well, only one to be exact), and takes way too long to get there. Honestly, I think the story could have been told to a better effect in a short-story. At least, the usual characters and their interaction was spot on, so that's something. But it doesn't help that Spock's not there on the Enterprise, and Chekov gets to lead the investigation. Perhaps a bit more of the triumvirate would have helped me enjoy this novel more.
In the end an uninspired, disappointing reading experience.