Zoe Heriot played by Wendy Padbury
Zoe was a student at the Earth School of Parapsychology which emphasised logic and science. At first she lacked emotions, but this changed during her travels with the Doctor. She also possessed a photographic memory. Zoe was one of the few companions to meet the Time Lords. She left when the Time Lords erased all memories of her travel with the Doctor except for the first after the Doctor's trial in The War Games.