The ENTERPRISE - shortly after the discovery of the Romulan cloaking device - getscalled into neutral space to bring a diplomat to a planet which might be added to the Federation. On a neighborplanet a precious mineral is mined which is brought over every few years, when the enrgy-field obsuring the planet opens. Into this openeing time ENTERPRISE arrives and the crew learns, that the field doesn't react well to warp-engines - which another StaarFleet-Ship learned a short time before.
This activity calls the Romulans into the system and makes it a quite complicated place.
A solid SF-novel. Nothing especialle good or bad.