Name: The Abbess
Played by: Audrey Ardington
Home Planet: Gorgos
Species: Gorgon
More Information: The Nuns believed the Gorgon was biding its time until it could return home. However, the truth was, the Gorgon was seeking a talisman, with which it could activate a space portal and open a gateway to enable its people to swarm onto Earth and take over the world.

Name: Sister Helena
Played by: Beth Goddard
Home Planet: Earth
Species: Human
More Information: Leading her cloister of nuns in service of the mysteriously veiled Abbess, Sister Helena was on a quest to find an ancient talisman to restore her mistress to full power and fulfil the St. Agnes sisters' search of three thousand years.

Name: Bea Nelson-Stanley
Played by: Phyllida Law
Home Planet: Earth
Species: Human
More Information: Bea Nelson-Stanley is an old lady residing in Lavendar Lawns, a nursing home. She is suffering from Alzheimer's Disease. As the appearance of a mysterious nun sighted in the nursing home is investigated, Bea entrusts Luke Smith with an alien talisman which her husband, Edgar, gave to her. Bea later reveals that her husband had seen Sontarans. After the talisman is used to defeat the Gorgon, Sarah Jane Smith and Maria Jackson return it to Bea; she briefly sees a vision of her husband, but is not cured of her Alzheimer's as Maria had hoped.