Lucie Miller

Lucie's first appearance is Blood of the Daleks. Described as a "strong willed northern lass," Lucie is initially an unwilling passenger in the TARDIS, having seemingly been placed with the Doctor as part of a Time Lord witness protection programme. Lucie tells the Doctor that the Time Lords have placed her in his care because she has seen something important, but doesn't know what. Her initial attitude towards the Doctor is disdainful, but she recognizes that he's "about saving worlds".

In Horror of Glam Rock, Lucie unexpectedly encounters her 'Auntie Pat', Patricia Ryder, the drummer of a failed band called Methylated Spirits, in 1974. As this is over a decade before Lucie is born, Pat is sceptical, but grows to like her as the story develops.

After several more adventures with the Doctor, the events of Human Resources reveal much of the mystery surrounding Lucie: the Time Lords learned that the Celestial Intervention Agency have been tracking Lucie because they believe she would become a terrible future dictator within Europe, and attempt to alter her present to prevent this. But when she applies for a job in an office building, which is part of another CIA plot, the Time Lords place her with the Doctor to protect her from the effects of exposure to too much CIA technology. But in reality, a woman named Karen, who had been interviewed on the same day as Lucie, is the actual future dictator, and the Time Lords have either been tricked or simply made a mistake. At the end of the story Lucie and the Doctor continue to travel together in the TARDIS.

Lucie meets her Aunty Pat again in The Zygon Who Fell to Earth, set about a decade after Glam Rock. Pat has now married a Zygon who has rejected the warrior ways of his people. But when his superiors come looking for him, Pat is murdered. Her husband, unwilling to tell Lucie, permanently takes on Pat's form, becoming the Aunty Pat that Lucie grew up knowing. The Doctor finds out about this, but is sworn to secrecy.

At the end of Vengeance of Morbius, the Doctor is seemingly killed while trying to prevent the Time Lords from being overthrown. They send her home and she resumes her normal life. However, six months later, she is kidnapped by The Headhunter, who has taken the Doctor's abandoned TARDIS, and together they locate him on an obscure water planet called Orbis, where he has been quietly living for the last 600 years of his life. Orbis is then suddenly destroyed and the Doctor and Lucie resume traveling in the TARDIS.

Finally, in Death in Blackpool, Lucie discovers the truth about her Aunty Pat being a Zygon. She also learns that the Doctor knew and didn't tell her. She sees this as a betrayal of their trust and chooses to stay home, parting ways with the Doctor.