The Voltranons tried to destroy all life on Earth but were stopped by the Doctor and Victoire Vignes.
Decades later, they tried again, sending an agent named Toprak, who was disguised as an inspector, to steal the bacteria Victoire used in making cheese. Toprak was stopped by the Seventh Doctor and Chris Cwej, with the Doctor claiming that humanity could stop anything the Voltranons would do. (PROSE: Culture War)
Ace, who was using a time hopper around 19th century Paris, reunited with the Doctor to stop a Voltranon invasion. (PROSE: Set Piece)