Read again? Eventually.
Book set somewhere between Trek I (The Motionless Picture) and Trek II. On the "exciting" meter it's closer to I than II.
The Enterprise is diverted from R&R at Starbase 12 to deal with UFP people being kicked off a planet by the new government. It would normally be a diplomatic matter, but this planet--Dekkanar--happens to be part of a Distant Early Warning line that monitors the Neutral Zone between the Federation and Klingon (and Romulan?) space. Losing access to this planet means losing the command post and operations hardware for the 'Firechain.'
Some plot conveniences: No weapons, shields, active scanners (for diplomatic reasons) and no transporters (the planet's star is conveniently in a sunspot phase at just the right convenient frequency to scramble transporters, thereby requiring shuttles to get the Federation people off the planet).
As all this is developing, we're taken to a Klingon spacedock where an experimental D-7 battlecruiser is being readied for its proving flight. This ship will have no crew on-board--instead, it is controlled via a tether from a scout-class Bird of Prey (like the ship Kirk and crew go back in time with in the 4th movie). Hakkarl will be able to fight while cloaked and can pull maneuvers no crewed battlecruiser could manage.
The Klingons are in the same vein as John Ford's "The Final Reflection." [it differentiates between the Klingon language Ford used and that developed by Marc Okrand]. Don't like Morwood's take on Klingons; they're fine on the surface, but seem "off" in some ways--too human-like, prissy (mentally fussing over the smell of a space suit?). Like so many other authors' inability to "get" Vulcans, Morwood doesn't seem to really "get" Klingons.
The Klingon baddie Kasak was aboard the ship the tribbles were beamed to in the TOS episode "The Trouble with Tribbles." His fortunes suffered with the rest of that crew and Koloth, their captain. When he finds out that he's facing the evil James Kirk and his notorious ship, he wants revenge, but he goes about it in a whacked-out, convoluted manner.
Book seems to drag. There are good moments, but this isn't an exciting book, nor is it really engaging like "Strangers From the Sky" or "Spock's World." Still it's much better than "Windows on a Lost World." The ending is a bit weak, with the suddenly-insane Kasak bringing about his own downfall in time for the book to end. Locking phasers on a point. Man, am I ever tired of "Star Trek" right now.