The Doctor and Mel are attacked by the Rani, and the Doctor immediately regenerates. He must remember who he is and come to terms with his new form to stop his old foe. From dystopian housing blocks to time-traveling vacationers to a planet of ice, the Doctor and Mel help the downtrodden fight those who oppress them.
With his new companion Ace, The Doctor begins his transformation into a great manipulator, a master chess player, although it is a slow build. Daleks, Cybermen, Nazis, Happiness Patrols, and psychotic clowns challenge the Doctor as he tries to mold Ace and put to rest his personal history.
The Doctor and Ace continue their journeys and continue to discover new layers about each other. The Doctor finds himself manipulated by a future Doctor, Ace is forced to confront personal horrors of her past, and the mystery of the time storm that abducted Ace from her life in Perivale is finally solved.