Having started at the end of the Eighth Doctor's adventures with Lucie Miller, I circled around to the beginning, and "Blood of the Daleks." This two-part story from January 2007 starts with an unexpected arrival in the TARDIS: a young human woman, Lucie Miller, who surprises the Doctor as much as he and the TARDIS surprise her.
Although Lucie's memory has been impaired, she and the Doctor piece together that the Time Lords have placed her in the TARDIS and in the Doctor's care. Each is resentful of the other for that imposition.
On the planet Red Rocket Rising, the Doctor and Lucie rescue two women from an angry mob. One is Acting President Eileen Klint, trying to hold together a semblance of society after an asteroid crashed into the planet, creating environmental disaster. The other is Asha, formerly an assistant to a dead scientist, Professor Martez. The professor had been engaged in experimentation on humans - first on cadavers, then on the living - that Klint finds abominable.
Klint has sent out a distress call, seeking rescue from other human colonies. Instead, a Dalek spaceship arrives, promising rescue and friendship. The Doctor tries to warn Klint about the Daleks and their duplicity, but Klint makes arrangements for the Daleks to land.
The plot melds a number of story lines, including the humans' realization that the Daleks aren't what they claimed to be, Professor Martez's experiments and the nature of being human, and the wary relationship between the Doctor and Lucie. A powerful start to a new series of adventures.