Susan Foreman is a character in the British science fiction series Doctor Who
. She is the granddaughter of The Doctor, the show's lead character, and like the Doctor originates from the planet Gallifrey. Her real name is never revealed: "Susan Foreman" is an alias she chooses when she and the Doctor spend several months living in London in 1963 - her last name is derived from the name of the I.M. Foreman scrapyard where the Doctor's ship, the TARDIS, is hidden. Later, she continued to be referred to as Susan, even by the Doctor.
As a student of Coal Hill School, Susan found herself continually frustrated at knowing facts about history and science her classmates - and her teachers - were ignorant of, ranging from working with the 4th and 5th dimensions in mathematics, to knowing that the UK will someday adopt decimal-based currency (a real-life prediction for the series, as the UK didn't decide to convert over until several years after the episode aired). Her ability to be brilliant in some areas and deficient in others attracts the attention of two of her teachers, Ian Chesterton and Barbara Wright, with Barbara becoming concerned for Susan's welfare when she learns the home address Susan gave the school was a scrapyard.
One day, Susan is followed "home" by the teachers, who investigate the scrapyard and find the TARDIS humming inside. After a tense first encounter with the Doctor, they force themselves inside and discover its true nature. Their secrets unraveling, the Doctor and Susan reveal some of their background, with Susan indicating she comes from "another time, another world". Needing to keep their secret from spreading, the Doctor - ignoring Susan's protests - kidnaps Ian and Barbara, who become reluctant participants in a number of adventures. Despite the initial duress, the group soon becomes a family, with Ian and Barbara acting as surrogate parents to the teenaged Susan.
But Susan begins to grow up, and, during an adventure fighting the Daleks on a ravaged 22nd-century Earth, falls in love with a resistance fighter named Tom Campbell. Seeing her torn between staying on Earth with Tom and helping rebuild Earth, or continuing to travel with her grandfather, the Doctor makes the difficult decision to lock her out of the TARDIS, telling her in an emotional farewell that she must "go forward in all your beliefs and prove to me that I'm not mistaken in mine." Despite his positive intentions, the Doctor regrets leaving Susan and soon "adopts" his next companion, Vicki, as an unambiguously surrogate Susan.
Susan's life after leaving the TARDIS has not been chronicled on TV. In the 1983 special The Five Doctors, the First Doctor is reunited with Susan, now in her 30s or early 40s, when she is teleported along with him (and three of his later incarnations) to the Death Zone on Gallifrey. Susan helped her grandfather defeat a lone Dalek, assisted the Fifth Doctor's companion Vislor Turlough in defending the TARDIS, and briefly met her grandfather's Second, Third and Fifth incarnations (as well as assorted other companions) before being presumably returned to her own time. Her fate after that has yet to be revealed on TV.