A handmaid to Cassandra, she joined the Doctor and Steven Taylor in the TARDIS after the fall of Troy. Her travels were cut short when she sacrificed herself on the Spar to save her friends. A collision between the First and Second Doctors' TARDISes meant that she spent three more months with them in a timeline that was later averted by her own choice to defeat the Dalek fleet.
The first of the Doctor's companions to die whilst travelling with him, her death weighed heavily on his mind.
Katarina belonged to a poor family who lived near Troy. As they had little money and stopped being able to feed her, she wanted to be a handmaid to a priestess. She told this to the Seventh Doctor when he met her as a young girl in 1240 BC, after which he gave her a gold coin in exchange for water to alleviate her family's poverty. (PROSE: An Unfulfilled Dream)
She went on to fulfil her ambition and become handmaid to Cassandra, who chose her because she predicted that she would die. (PROSE: Scribbles in Chalk) She was little more than a slave and, when she told her mistress of her visions of the future, Cassandra told her that she would be put to death should she bring it up again. (AUDIO: Daughter of the Gods)
Travels in the TARDIS
Meeting the Doctor
Katarina was sent by Cassandra to spy on the First Doctor, Steven Taylor and Vicki Pallister, with the particular aim of gathering evidence that Vicki was a Greek spy. She befriended Vicki, who sent her to help the Doctor get Steven back to the TARDIS after he was injured by a spear. She tended to his wounds and joined him and the Doctor on their travels whilst Vicki remained behind. (TV: The Myth Makers)
In search of medicine for Steven, the Doctor landed on a planet that went through a temporal anomaly and where they met the Lakhotha tribe. Drinks-Pools-Dry showed an interest in Katarina. She and her companions enjoyed a meal there before they all began to violently transform into animals and plants due to the Conduit, although Katarina and Steven transformed more slowly. They rushed to the TARDIS where the two humans lost their memories of the events and Steven's wounds returned, prompting them to leave in search of help once more. (PROSE: Scribbles in Chalk)
In the Time Vortex, the TARDIS collided with a future version of itself, preventing the crew from landing on Kembel and instead materialising on Urbinia. Katarina, the Doctor and Steven spent three months there due to the damage sustained by the TARDIS, during which Katarina had nightmares about her death and believed that her descent to the Underworld was overdue.
Katarina met the Second Doctor, Jamie McCrimmon and Zoe Heriot during an attack by the Daleks and learnt that her beliefs about her overdue death were correct. She and the Second Doctor discussed their options and she reached the conlusion that she had to die in order to prevent the invasion. She was aboard the Second Doctor's TARDIS when he prevented the temporal collision, erasing her three months with the Doctor and Steven and setting them back on the course to Kembel. (AUDIO: Daughter of the Gods)
After landing on Kembel, Katarina remained in the TARDIS with Steven whilst the Doctor looked outside for drugs. She administered tablets to Steven at Bret Vyon's instructions and fled with the two men into the jungle when Daleks surrounded the ship. The Doctor joined them and they went to the spaceport where they stole the Spar and crash-landed on Desperus. Katarina and Steven made sure to prevent intruders from boarding the ship, but Kirksen managed to stow away. (TV: The Daleks' Master Plan)
The Spar took off for Earth and Katarina checked to see if a door was secure, upon which Kirksen emerged and held her hostage, pulling her to an airlock to blackmail the Doctor into returning the ship to Kembel. To save her friends, she activated the airlock door and expelled herself and Kirksen into space. (TV: The Daleks' Master Plan) As she fell through space, struggling to breathe, she thought of how the gods liked sacrifices before dying. (PROSE: Skipping Song) She was certain her death had been foretold and that she was doomed to die. (TV: The Daleks' Master Plan)
Katarina's body was recovered from space by River Song and subsequently stolen by the Nine for his collection of the Doctor's companions. When he attempted to scan Katarina's mind to determine her identity, the residual artron energy in her body gave her enough mental strength to distract the Nine at a crucial moment, allowing Charlotte Pollard, Liv Chenka, Helen Sinclair and Bliss to defeat him. (AUDIO: Companion Piece)
In the afterlife, Katarina found herself without a coin and thus unable to cross the River Styx. Thanks to the intervention of the First Doctor, or her idea of him, she was able to find her way not only to Asphodel, where the souls of those who had done neither good nor evil went, but to the Elysian Fields, the abode of the blessed. (PROSE: Katarina in the Underworld)
Katarina's death weighed heavily on the Doctor's conscience. The First Doctor said that he would always remember her as one of the daughters of the gods (TV: The Daleks' Master Plan) and the Second Doctor said that he would never forget her. (AUDIO: Daughter of the Gods) Inside the inner landscape of the Seventh Doctor's mind in a hell haunted by his guilt, Ace came across the ghost of Katarina in the form of an eternally frozen girl of ice. (PROSE: Timewyrm: Revelation) The Doctor also once saw Katarina, with Sara Kingdom and Adric, amongst his past guilts. (COMIC: The Last Word)
On the ruined world of Adeki, the Seventh Doctor found one of several Gwanzulums, beings who used their shapeshifting powers to pass themselves off as some of the Doctor's past companions, including Katarina. Before he realised the ruse, the false Katarina tried to have him take her off the planet. (COMIC: Planet of the Dead)
While in the Divergent Universe, the Eighth Doctor was shown an illusion of Katarina by the Kro'ka. He stated that he regretted taking Katarina from her own time and giving her hope, only for her to be killed shortly afterwards. (AUDIO: The Last)
Katarina did not believe that she was special nor worthy of recognition. As a result, she believed that she would go to the Place of Perfection where those who had not accomplished great deeds or had not been especially noteworthy would go. Jamie McCrimmon challenged this, telling her that she was better than that. (AUDIO: Daughter of the Gods)
She asked very few questions, preferring to watch and learn, something that the First Doctor believed that Steven could learn from her. (TV: The Daleks' Master Plan) Despite the Doctor's protestations, she believed that he was Zeus and that the TARDIS was a temple transporting them to the afterlife. (TV: The Myth Makers, The Daleks' Master Plan) She continued to use the TARDIS as a place of prayer regardless of what the Doctor said. (AUDIO: Daughter of the Gods)
She followed the Doctor's instructions to the letter and was anxious when she went against the Doctor in the interests of aiding Steven's recovery. She had no knowledge of more technologically advanced ages. As a result, the Doctor educated her on some of these items, for example the purpose of keys. She told him that she felt safe with him. (TV: The Daleks' Master Plan)
She was certain that she was doomed to die, as had been foretold. She deliberately brought about her own demise to save the lives of the First Doctor, Steven, Bret Vyon, and "perhaps the lives of all the other beings of the Solar System". (TV: "The Traitors")
Behind the scenes
Doctor Who producer John Wiles and his production team decided to write out Katarina as soon as possible to get around the writing challenges of a character so very unused to modern concepts, and to whom the Doctor would have had to explain everything — for example, Katarina did not even know what a key was. They decided to do so in the most dramatic way possible.
Katarina was the first companion of the Doctor to die; she would be followed by Sara Kingdom later in the same serial. However, the first long-term companion to die on-screen would not be until Adric's death in Earthshock.
Only one episode featuring Katarina is present in the BBC Archives.