A Drelleran expedition journeyed to Earth where they landed in Kent in 1895. Lord Jack Corrigan gained the confidence of the Drellerans before attacking them and seizing their spacecraft, the Aeolus, desiring interstellar space travel to glorify the British Empire.
A peaceful, trusting people, the Drellerans were subjugated by Corrigan and his heavily armed crew of twenty-four. When they could bear this no longer, they infected the humans with a virus that compelled them to return to Earth to destroy their own race.
A number of Drellerans followed to ensure this occurred. They teleported the Fourth Doctor, Leela and Alison Foster aboard their ship and told them of their plan. The visitors told them that humanity had changed in the centuries since Corrigan's time. The Drellerans injected them with an anti-virus and returned them to Space Dock Nerva, where Lord Jack was, and the virus was destroyed when they came into contact with him. (AUDIO: Destination: Nerva)