Susan (Dr. Who and the Daleks)

Susan was the granddaughter of the human scientist Dr. Who, who invented the time and space machine Tardis. She lived with him and her elder sister Barbara in a cottage in England.

Biography
Susan shared her grandfather's genius and passion for science, and this contributed to her being a highly precocious child.

She accompanied Dr. Who on his first trip to the planet Skaro in Tardis, as did Barbara and her boyfriend Ian Chesterton. During her travels, she met the Daleks and then an ancient Roman legion in 64 AD. (Dr. Who and the Daleks, ST: The House on Oldark Moor)

They subsequently travelled to Oldark Moor and met Count Tarkin. (ST: The House on Oldark Moor)

After Ian and Barbara had seemingly left Tardis, she and her grandfather travelled to Mars with his niece Louise, where they once again encountered the Daleks as well as the telepathic native Martians. After Louise was captured by the Daleks, Dr. Who learned that the Martian Sphinx was in fact an ancient weapon whose secret had been forgotten. He was able to reactivate the Sphinx and used it to destroy the invading Dalek forces, only moments after he had rescued Louise from the Dalek Flying Saucer. (DWMS: Daleks Versus the Martians)

Dr. Who, Susan, Louise and a police constable named Tom Campbell later travelled to London in 2150 and found that it had been devastated by a Dalek invasion years earlier. Once there, she assisted in freeing Earth from Dalek occupation. (Daleks' Invasion Earth 2150 A.D.)

Behind the scenes

 * Susan was based on the Doctor's's granddaughter Susan Foreman, who was an older and almost entirely different character. While a few reference works indicate that Susan's full name is Susan Who, this is not supported by any on-screen evidence. On-screen, her grandfather was literally called Dr. Who, so if Susan's last name truly is "Who", this would imply that Dr. Who is her father's father.