However, the doctor soon learns that command is a double-edged sword when Kirk disappears without a trace. Desperately trying to locate his captain, McCoy comes under pressure from Starfleet to resolve the situation immediately. Matters go from bad to worse when the Klingons arrive and stake their own claim on Flyspeck
Then another, more deadly power threatens them all, and suddenly Dr. McCoy and the Starship Enterprise find themselves pitted against an alien fleet in a battle they have no hope of winning.
(From the Star Trek Series shelf.)