The Enterprise is caught between the Klingons and another race who both want a supply of super weapons. A pretty amusing book.
Another excellent story involving the Kreel -- most despised aliens in the STTNG universe. This story takes place on a planet where alien mass weapons of destruction are discovered by the Kreel, who don't know how to use them. One of the funniest STTNG books ever.
Out of the first five numbered Next Generation books, I think this is the best one, and my favorite. First of all Peter David makes parts of the story very funny. Second the story is just good. The Kreel and Klingons-enimies-are both on the Enterprise for a Diplomatic mission. You will have to read this for yourself to find the middle, but the end is that the "mission" is a test to make the Enterprise crew learn.
Deep in the uncharted regions of our galaxy, a primitive, warlike race--the Kreel--have stumbled upon weapons powerful beyond their wildest imaginings. The Kreel have used those weapons to attack their most bitter enemies--the Klingons.
Now Captain Jean-Luc Picard and the crew of the U.S.S. Enterprise have been called in to mediate the dispute. The Enterprise will ferry diplomatic teams from the two warring races to the source of their conflict--the mysterious planet where the weapons were discoverd, in an attempt to find a peaceful solution to the conflict and discover the origins of the super-powerful weapons before the entire galaxy erupts into full-scale war . . .