K-9 and Company is a one-episode television pilot, for a proposed 1981 television spin-off of the British science fiction television series Doctor Who. It features former series regulars Sarah Jane Smith, an investigative journalist played by Elisabeth Sladen, and K9, a robotic dog voiced by John Leeson. Both characters had been companions of the Fourth Doctor, but they had not appeared together before. The single episode, "A Girl's Best Friend", was broadcast by BBC1 as a Christmas special on 28 December 1981, but was not taken up for a continuing series.

Plot

Sarah Jane Smith visits her Aunt Lavinia, who was occasionally mentioned but never seen in Doctor Who. When she arrives at her aunt's house, though, she finds that her learned relative has left early for a lecture tour in America, Christmas notwithstanding. Sarah is thus left disappointed by the prospect of another holiday without family. Lavinia's ward, Brendan Richards, breaks her moment of reflection on her aunt's sudden disappearance. After picking him up from the railway station, they return to the house and discover a large crate that has been waiting for Sarah for a number of years. When they open it, they discover a mechanical dog named K9. Upon activation, it tells Sarah that it is a gift from the Doctor.