Emily Blandish was a companion of the Doctor before being dropped off in 1949.
Biography
The Doctor, under the alias Dr Smith, was trying to stop the Sodality from existing, so that hundreds of time sensitives would not be killed by them. After failing to gain the support of the High Executioner in erasing the Sodality from history, the Doctor departed in his TARDIS.
The Doctor set events in motion so the "Child of Time" would gain its full powers and stop the Solidarity's plans. The Doctor left in his TARDIS with the unconscious High Executioner, who was now suffering from amnesia. The Doctor dropped off the High Executioner in 1949, where she called herself by her real name, Emily Blandish, and helped the Doctor defeat Mestizer in his relative past. (PROSE: Child of Time)
She was found dressed only in pink pyjamas at the site of an explosion in Shoreditch by a patrolling policeman. The mystery of her arrival led to her story being taken up by the press, who paid for her to stay in the guest house of a Mrs Beardsley.
Some time after her arrival, Emily was visited by a "fixer" named Honoré Lechasseur, who had been hired to find a gentleman called the Doctor. Emily had no recollection of such a gentleman, but when Honoré mentioned he had been hired by a woman called Emily Blandish, Emily instantly remembered this was her own name.
Emily soon found herself at the centre of a plot of Nazi sympathisers led by Mestizer to steal the "Cabinet of Light" for their own ends. With the help of Honoré, she managed to escape the Nazis. (PROSE: The Cabinet of Light)
Afterwards, Emily and Honoré kept in touch and built a strong relationship. After spotting the same man at the same time, Honoré realised that Emily was a time sensitive. They travelled to an alternative 1984, where they tried to work out how to get back to their own time. When they returned, they ensured that the future they had witnessed never came about. (PROSE: The Winning Side)