Remembrance of the Daleks

S25 E1: The Doctor and Ace return to the England of 1963, the same time as the Doctor and Susan used to live in a scrap yard in Totters Lane. Returning to the school where Susan studies, the Doctor discovers that all is not as it should be. It soon becomes clear that a war between two Dalek factions is being fought, while they both seek a device the Doctor had hidden on Earth on his last visit.