Sara Kingdom Sara Kingdom was a Space Security Service ( SSS ) agent who turned against Mavic Chen , the traitorous Guardian of the Solar System . With the help of the First Doctor and Steven Taylor , she defeated Chen and his secret allies , the Dalek s . The price of victory was , however , her own life . ( TV : " The Daleks ' Master Plan " ) Biography . Early life and career . Sara had two brothers , both fellow SSS agents — David Kingdom and Bret Vyon , the latter of whom the Doctor also encountered on Kembel . ( TV : " The Daleks ' Master Plan " , AUDIO : " The Destroyers " ) Sara joined the SSS at the age of 7 . ( AUDIO : " The Sontarans " ) She was a high - ranking and original member of the SSS . At the foundation of the Space Security Service , she was chosen by Colonel Marc Foster and the artificial intelligence Compuvac as an agent in charge of the organisation ' s field operations . As a woman , she was chosen for the first mission of the agency and she was sent to Barzilla to divert the plans of the Golden Dalek from Earth to that planet , by spreading the news of its gold mines among the Dalek spies . The trap worked , the Dalek forces were annihilated by their enemy alliance and she was praised for the success of the mission . ( PROSE : " The Outlaw Planet " ) Trained and efficient , Sara had the strength of ten men . She was sent to planet Vara to rescue the kidnapped Professor Lomberg and prevent him to be forced by the Daleks to give them a formula of a metal for a new outer casing which would have made them unstoppable . She leaked in the Dalek slave camps , found the Professor and helped him to give the Daleks a wrong formula . That led into blowing up the camp and foiling the Daleks ' plans . ( COMIC : " " ) She was charged to investigate the leaking of confidential information that the Daleks were using to attack Earth strategic bases . She discovered the new Dalek emperor was able to read the thoughts of Earth ' s defence scientists through radio waves . She made up a plan that employed those scientists as a bait for the Emperor , while human forces attacked and wiped out the Dalek fleet of the Emperor . ( COMIC : " The Brain Tappers " ) Sara , with fellow SSS agents Jason Corey , the humanoid robot Mark Seven and her brother David Kingdom , encountered the Daleks in a brief confrontation early in her career . David went missing at the end of the mission . ( AUDIO : " The Destroyers " ) Mark Seven had written a file about the mission where David Kingdom got lost , which Mavic Chen consulted when he and Bret Vyon unexpectedly met Sara in 3999 ; she was supposed to be stationed on Venus at the time . Sara received a surprise promotion from Chen at this time . ( AUDIO : " The Guardian of the Solar System " ) Adventures with the Doctor . On Earth the following year , she was briefed by Chen and was told her brother was a traitor . In an experimental testing facility , she found the Doctor , Steven Taylor , and her brother , the last of whom she shot to death . Sara would have done the same to the Doctor and Steven , but all three were accidentally transferred from Earth to Mira by cellular transportation . There she learnt , to her horror and grief , that her unquestioning obedience had not only led her to unjustly kill her brother but had prevented Vyon from warning Earth of the Dalek plot . She joined the Doctor in his fight . Together they stole a Dalek capsule and set off back to Kemble while , on board , managing to create an exact copy of the taranium core . Arriving back on Kemble , Sara was more than displeased to see Chen allied with the Daleks . She then escaped , after handing over what Chen believed was the taranium core , with the Doctor and Steven in the Tardis , taking the real taranium core with them . With Steven and the Doctor , Sara took a short , stress - free trip to ( in Sara ' s terms ) long - ago Earth . ( TV : " The Daleks ' Master Plan " , PROSE : " The Little Drummer Boy " ) After spending Christmas Day on Earth , Sara and the others spent six months having other adventures before once more getting involved with the issue of the Daleks and Chen . ( PROSE : " The Mutation of Time " ) Shortly after celebrating Christmas a ship tried to land inside the TARDIS , and she had to explore a desert island to discover when the TARDIS had gone after it crashed . Whilst exploring the island she fell of a cliff and broke her arm . When she found out that the desert island , and was relieved when it was revealed that it was the TARDIS emergency systems . When Natalie Lang tried to pilot the TARDIS they landed in Berlin . Sara was then captured by the policemen , though later escaped . ( AUDIO : " The Anachronauts " ) They visited 3999 , where Sara met Vyon and had an audience with Chen , which finally explained why she had been promoted in that year . ( AUDIO : " The Guardian of the Solar System " ) On a world covered in water they encountered a set of miners who had survived and earthquake in the mine . Here they were attacked by a tentacled creature . ( AUDIO : " The Drowned World " ) After further travels in the Doctor ' s TARDIS , " An Ordinary Life " , PROSE : " The Little Drummer Boy " ) they came upon a house in Ely that granted wishes ; after the adventure , a copy of her mind lived on inside it for thousands of years . ( AUDIO : " Home Truths " ) They later landed in London in the 1950s , when they were ejected from the TARDIS with the Doctor unconscious . She didn ' t like what she saw when there was an attack on Joseph Roberts house , due to him being Jamaican . After the Doctor and the TARDIS vanished she spent her time with Audrey Newman learning about life in 1950s England . Audrey later tasked Sara with looking after her daughter . When the Doctor reappeared , she found out what was going on and helped to destroy it . ( AUDIO : " An Ordinary Life " ) She , the Doctor and Steven helped other SSS agents fight the Sontaran s . After that , the TARDIS detected an unidentified time machine following them , leading them to return once more to the struggle against the Daleks . ( AUDIO : " The Sontarans " ) The Daleks turned against Mavic Chen ( who intended to betray them ) and killed him . The Doctor had returned to Kembel to activate the Time Destructor to finally stop them . The Doctor ordered his companions back to the TARDIS for their protection . However , Sara followed him , not knowing the nature of his plan but concerned it might fail . She was caught in the field of the Time Destructor and , being a human rather than a Time Lord , aged to death . As Steven and the Doctor watched helplessly , Sara died , her remains ageing to dust . ( TV : " The Daleks ' Master Plan " ) Undated events . A photograph existed in UNIT ' s Black Archive showing Kingdom standing next to UNIT Captain Mike Yates , who was primarily associated with the Third Doctor . ( TV : " The Day of the Doctor " ) Legacy . The death of Sara , as well as their other allies Bret Vyon and Katarina , caused Steven to confront the Doctor about the violence that seemed to follow him . ( TV : " The Massacre of St Bartholomew ' s Eve " ) In his seventh incarnation , on the ruined planet Adeki , the Doctor thought that he ' d found Sara Kingdom among others of his companions alive again and desperate to leave in the TARDIS . He learned that one of a race of shape - shifting Gwanzulum had used his sentiment in order to manipulate him into helping it escape the dead world . ( COMIC : " Planet of the Dead " ) Later , while in a Hell - like world composed of the Seventh Doctor ' s mind , Ace met an eerie , ghost - like recreation of Sara Kingdom among his companions who had died because of him . Ace didn ' t recognise her . ( PROSE : " " ) On the Space Security Service Station 7 , the Eleventh Doctor told Tranter that he had worked with Sara and Bret , prompting the station commander to comment that he had impressive credentials and must have started fighting the Daleks at a very young age . ( COMIC : " The Only Good Dalek " ) Reincarnation . The copy of Sara Kingdom ' s mind left behind in the house in Ely lived on into an age of Earth ' s history in which advanced technology had become almost non - existent . An academic named Robert befriended her , interested in hearing stories from her past . Eventually , Robert wished to take her place as the entity inhabiting the house , and the alternate Sara was given human form as an older woman . Robert drew the Doctor ' s TARDIS back to the house , and allowed Sara to choose whether to join with the Doctor ( in a later incarnation ) or to remain on Earth . ( AUDIO : " Home Truths " , AUDIO : " The Drowned World " , AUDIO : " The Guardian of the Solar System " ) This version of Sara later joined Steven , Ian Chesterton , Polly Wright , and Nyssa in being abducted by Borusa , utilising a Time Scoop , to an alternative version of the Death Zone on Gallifrey , where she met the Fifth Doctor and once again battled the Daleks as well as the Sontaran s . ( AUDIO : " The Five Companions " ) Personality . Sara was by turns aggressive , independent , and ruthless in her pursuit of what was right , a single - mindedness that blinded her to the larger implications of her orders . She used to be without mercy about any casualties among the Dalek slaves ( COMIC : " " ) or causing riots on other planets ( PROSE : " The Outlaw Planet " ) for the sake of her missions . Meeting the Doctor changed that , and she turned her formidable skill and intellect to the defeat of the Daleks . ( TV : " The Daleks ' Master Plan " ) Steven later commented that he and Sara became fast friends over the course of their travels and that their relationship might have developed further if Sara had survived . ( AUDIO : " The Anachronauts " )