The Enterprise crew receives a distress signal from a city that is covered by a dome. They are the descendants of a culture that has been involved in genetic engineering, creating a "perfect" society. Everyone has a role in the total makeup of the culture. Those that have been born with defects or lacking intelligence enough to contribute, have been eliminated. They have kept strangers out of mix because they feel they would prove contaminants. What is missing, however, is the need for creativity and challenge. The Enterprise has arrived because a star fragment threatens to destroy their world. At first, they are turned away but their leader realizes that without the aid of the crew, they are doomed. Into the mix comes Deanna Troi who develops feeling for the leader and he for her. Also, a young female engineer assists Jordi and starts to see that challenge and threat are an important part of life's journey. They have never had to face any such issues since their culture is stable and unchanging. This becomes the issue as this society has to face its unhappiness. A very interesting episode.