A CVE appeared near Ballustra. It was the size of Letrus and growing. It quickly grew larger than Ballustra.
The CVE let out pressure waves that caused earthquakes and tsunamis. Fifteen percent of the population was said to have died on the first day.
A joint military and scientific group set out to investigate the CVE. They took the Doctor's TARDIS. Romana II and Adric were taken prisoner and delivered to Letrus. There they were questioned by Marni Tellis.
The Farrian arrived through the CVE and attacked Ballustra, killing many. They were after Ballustra's Genellium. The nations of Ballustra banded together, forming a single effective defence force. After the Fourth Doctor closed the CVE generator in N-Space the Farrian were forced to recall their officers and retreat. They left behind the ground troops who helped in the reconstruction of the planet. A planetary defence force was developed to fight any further invasions. (AUDIO: The Invasion of E-Space)