Twin Forces of Evil — John B. Bolton

Capt Buckton, his crew and warship Pegasus are in the thick of it again. Capt Buckton spends several months in a very prestigious school and in the meantime his XO, Cmdr Ed Gilbert, is in temporary command of DSC-01 and he is unknowingly being closely monitored for a future command of his own.
Once JT finishes school and comes back to Pegasus, an old friend warns Fleet Command they are picking up distress calls from the Lambda System in alliance space. It is only at this point the alliance becomes aware of the danger and sends several ships to investigate. Capt Buckton is the task force commander, but the problem is the task force is a long way behind Pegasus which is already in the area.
Seeking food for their empire, the Akydaa and Wahaban forces begin their invasion of the alliance. Their choice of food comes as a huge surprise to the defenders.
For added turmoil, Fleet Admiral Jensen and his wife, who are on an extended vacation, are captured by the Akydaa and nobody knows.