Nepara functioned as a penal module for the Web of Worlds. The exterior was fashioned as a saucer-shaped dome. Individual prison cells had translucent walls with transparent windows and ample reading material. A wall dematerialized whenever a prisoner needed to be moved. An exercise yard existed nearby, but tranya was not served to inmates.
In 2269, after the collapse of the Fiilestii module prompted the arrest of Kirk as a scapegoat, he was remanded to Nepara. He was imprisoned in the cell neighboring Koust, a captured Dassik, to see how they would react to one another. Later, both prisoners were transported to the exercise yard at the same time to see if Koust would kill Kirk after driven to a rage following a session of mental torture. The confrontation led to talking and eventually to an alliance.
Spock and Balok were arrested for attempting to sabotage the antigravity controls of the Web of Worlds and were incarcerated on Nepara. At some point, Balok was secretly taken to a separate facility by Triumvir Tirak and replaced with an android duplicate. When Kirk, Spock and Koust began their escape, the Balok android accompanied them. The escapees met up with Hikaru Sulu, Leonard McCoy, Anne Nored, Louis Prescott, Zhang Xiaolu and several other security guards, who had broken into the prison to rescue them. Their escape craft was a type of atmospheric flyer. (TOS novel: The Face of the Unknown)
- Mure, warden