Dot Strong was the daughter of Harroll Strong and the twin sister of Jack Strong. She had a dead-white complexion, dark, serious eyes and red hair.
Dot accompanied her father and brother on an Earth-Mars expedition to Corbo, during which she and Jack were the only ones not captured by the devil-birds. The First Doctor found them, after rescuing the spaceship crew, and took them to the TARDIS. (PROSE: The Devil-Birds of Corbo) Before being returned to Earth, they had at least one other adventure with him when they travelled to Rhoos. (PROSE: The Playthings of Fo)