Nervala IV was the formerly inhabited fourth planet in its star system. A Starfleet research station was located on this planet. The planet generated a distortion field, which prevented the use of transporters and shuttles. The distortion field could only be penetrated when Nervala moved closer to its primary, which happened every eight years. The planet also experienced earthquakes from time to time.
In 2361, the crew of the station was evacuated by the USS Potemkin, led by Lieutenant William T. Riker. During the evacuation a duplicate of Riker, Thomas Riker, was created by a transporter accident; Thomas remained on the planet while Will Riker made it back to the Potemkin.
In 2369, the USS Enterprise-D visited the planet to retrieve the data left by the research team. During the mission, Thomas Riker was discovered and rescued and with his help, the research data was recovered. (TNG: "Second Chances")