Sara Kingdom was an agent of Mavic Chen's Space Security Service, her exemplary record meant that she was assigned to hunt down and eliminate those responsible for forming a treacherous alliance with the Daleks. Sara was told that this group included the Doctor, Steven Taylor and fellow SSS agent Bret Vyon, her brother.

She followed Karlton's orders and on encountering the group, she gunned her brother, Vyon down. Eventually she was persuaded to join forces with the Doctor after he proved to her that Mavic Chen was the true traitor.

After a brief encounter with their old antagonist and fellow Time Lord, the Meddling Monk, and after traveling to planets such as Mira and Tigus they all arrive back on the planet Kembel. 

Sara helped keep the Taranium Core out of Dalek hands until their Time Destructor was ready to be activated. She activated it herself, wiping out the entire Dalek task force but aging herself to death in the process (V).

Jean Lyndsay Torren Marsh was Born in London on 1 July 1934. She became interested in show business while taking dancing and mime classes as therapy for a childhood illness.

After attending a charm school and working as a model, she started acting in repertory and took voice lessons. Her repertory work was supplemented by a number of film appearances as a dancer. She also appeared as a dancer in a number of films including "Will Any Gentleman" in 1953, during which she met and later married the future third Doctor Who, Jon Pertwee.

She then spent three years in America, appearing in Sir John Geilgud's Broadway production of "Much Ado About Nothing" and numerous TV shows, including an episode of "The Twilight Zone". Returning to London, she won roles on stage, film and TV. It was during this period that she appeared in Doctor Who, first as Princess Joanna in "The Crusade" and then as the Doctor's companion, Sara Kingdom in "The Daleks' Master Plan" , (only one story - but it was the twelve-episode

"The Dalek Masterplan").

In the late sixties she co-created with Elieen Atkins, and starred in as the maid Rose in London Weekend Television's long running TV series "Upstairs, Downstairs". Since then, she has maintained a very busy career in the theatre, on TV - including a starring role in the US sitcom "9-5" and films such as "Return to Oz" and "Willow". She also co-created another successful series, "The House of Elliot" .

Jean is known as an author publishing several novels.  She has also appeared in "Doctor Who" episodes "Battlefield" (7D) as Morgaine and "The Crusade" (P) as Princess Joanna. Recently jeanhas appeared as Thyrza Grey in the 1996 TV movie "The Pale Horse", the movie "Monarch" in 2000 and in the same year in the TV mini series "Ghosthunter" as Mrs. Crocker.