Kate Stewart

Dr **Katherine Sally Lethbridge-Stewart**, known professionally as **Kate Stewart**, was the Chief Scientific Officer at UNIT. She was the daughter of Fiona and Alistair Gordon Lethbridge-Stewart and the mother of Gordy and another child.

Kate spent her youth not knowing of her father's activities with extraterrestrial beings, believing whole-heartedly that his life consisted of a boring and simple military job. She and her mother spent much time ironically joking that he was constantly off on amazing adventures when they both knew the "truth." Kate would not begin to scratch the true surface of her father's life until years later when she shared an encounter against the Great Intelligence with him. She spent some time investigating UNIT and her father's ties to it and soon joined the organisation, rising to its top position and changing it to be a more scientific, peaceful group.

As the leader of UNIT, Kate encountered the Doctor many times during encounters between Earth and alien threats, becoming similar to the Doctor as her father had been. She was at the forefront of the peace treaty between humanity and Zygons on Earth since 2013.

## Biography

### Childhood

Katherine Sally Lethbridge-Stewart was born to Fiona and Alistair Gordon Lethbridge-Stewart three years into their marriage, which lasted eight years. As a child, her parents never told her of her father's work at UNIT; she was only aware that he was a military man and was under the impression that it was a boring job. She would often pretend that his absences were due to him having amazing adventures rather than the boring military operations that she believed he was involved in. (HOMEVID: Downtime)

Kate grew estranged from her father. On 25 September, 1990, she gave birth to a son whom she named Gordon James Lethbridge-Stewart, In 1995, Kate and Gordon were harassed by students of the New World University, who believed that she might be able to lead them to the Brigadier. Frightened, she reconnected with her father and briefly fought alongside him and Sarah Jane Smith against the New World group. Following the Great Intelligence's defeat, she entered into a friendlier relationship with her father and ensured that he could have a relationship with the grandson whom he had not previously known about. (HOMEVID: Downtime) Kate later married and had a second child, but her relationship ended in divorce. (TV: Death in Heaven)

### Reorganising UNIT

Guided by her father and instilled with the mantra that "science leads", a belief for which the Brigadier credited the Doctor, Kate joined UNIT, going by "Kate Stewart" to avoid unwanted favours and so that she would be judged on her own merits. She rose to the position of Chief Scientific Officer and dragged the organisation "kicking and screaming" to her vision of its scientists leading, a process which she did not find especially fun. (TV: The Power of Three)

During the Year of the Slow Invasion, Kate freighted Shakri cubes from all over the world for testing and learnt little about them. After detecting a spike of artron energy, Kate met the Eleventh Doctor and, some days later, summoned him and Amy Pond to the Tower of London via his psychic paper. She attempted to warn the governments of the world of the cubes when they started their countdown and, once the incursion was over, she bid farewell to the Doctor, who had worked out that she was the Brigadier's daughter. (TV: The Power of Three)

### Trouble At The National Gallery

UNIT had in its possession a picture of Kate with River Song whilst the latter was wearing her Demons Run garb, as well as a photo of Kate with Clara from her "previous visit". (TV: The Day of the Doctor)

She ordered the airlifting of the TARDIS to London, to the agitation of the Eleventh Doctor. Kate summoned him there under the royal orders of Elizabeth I, giving him a sealed letter from the Queen and proving her credentials by showing him the impossible painting Gallifrey Falls No More within the National Gallery.

The letter decreed that the Doctor be made curator of the Under Gallery and that he be summoned should there be any disturbance there. Kate led the Doctor and Clara Oswald to the scene of the disturbance. There, she showed them more paintings, all landscapes with glass on the floor next to them. When the Doctor jumped through a time fissure and met the Tenth Doctor and the War Doctor. Clara attempted to follow him before Kate restrained her.

As she left the room to request important UNIT files, Kate was accosted by a Zygon who had escaped through one of the paintings and then took her image and pretended to be the real Kate to Clara Oswald. Osgood saved her from the Zygon nest. Kate, along with McGillop and Osgood, confronted their Zygon doppelgangers in the Black Archive. Kate ordered the countdown to detonate the Archive with a nuclear warhead which would not only prevent the Zygons from having control of the many weapons stored there but would also destroy London in the process. The Zygon used Kate's voice to stop the detonation, but Kate countermanded the order.

Kate and her Zygon counterpart bickered over the detonation, before the War, Tenth and Eleventh Doctors triggered the Black Archive's memory modifiers to confuse everybody in the room as to whether they were a Zygon or a human. The two Kates stopped the countdown, and negotiated a peace treaty. (TV: The Day of the Doctor)

### Early Actions With The Twelfth Doctor

When the Cybermen emerged from St Paul's Cathedral in the 21st century, Kate arrived with Osgood and UNIT and took Missy and the Twelfth Doctor into custody. She told the Doctor that he was President of Earth and worked with him to battle the Cybermen. When the Cybermen attacked the plane Boat One under Missy's command, part of the fuselage blew off and Kate fell out. She was saved by her father, who had been converted into a Cyberman, and returned safely to the ground. (TV: Death in Heaven)

### Later Actions With The Twelfth Doctor

When Missy returned and froze all the planes on Earth, Clara came to UNIT and Kate helped her contact Missy. (TV: The Magician's Apprentice)

Kate and UNIT went to investigate a Zygon invasion that broke out after a splinter group decided a peace treaty with humans was unacceptable. She was determined to bomb the rebel Zygon settlement, but the Doctor convinced her that this would only make the situation worse – threatening to radicalise every peaceful Zygon on the planet.

Kate followed a lead to Truth or Consequences in New Mexico to try and find the root of the uprising. Here she encountered the one remaining inhabitant of the town, police sheriff C. Norlander, who explained how the trouble started – the accidental revelation of a young Zygon in true form who "hadn't learnt to preserve his body print" had caused panic, distrust and violence within the human population. As the truth of what had really occurred began to dawn on Kate, she realised that Norlander was, in fact, a Zygon rebel agent. (TV: The Zygon Invasion)

She was then attacked but managed to kill the Zygon, before taking its place to fool the High Command. Kate was present in the Black Archive when the Twelfth Doctor forced her to become an ambassador for the human race in an attempt to negotiate a new peace treaty alongside the Zygon High Command leader Bonnie in which a standoff occurred involving the Osgood Box. However, her memories of the Box were soon erased. (TV: The Zygon Inversion)

## Personality

Kate disliked the use of weapons, refusing to take a gun from Sarah Jane Smith when offered, (HOMEVID: Downtime) though by the time of the 2010s and 2020s she would, when necessary, use a gun. (TV: The Zygon Inversion) When she took over UNIT, she enacted great changes to favour scientific approaches over military means. (TV: The Power of Three)