In this serial, the Doctor (Patrick Troughton) and his travelling companion Jamie (Frazer Hines), shortly after losing the TARDIS, are transported to 1866, where the Daleks force the Doctor to help them in their latest plot to implement the human factor into Dalek brains in order to 'humanise' themselves into even deadlier living weapons. This serial marked the debut of Deborah Watling as the Doctor's new companion, Victoria Waterfield. It is also notable for introducing the Dalek Emperor. Only episode two, the episode in which Victoria first appears, is held in the BBC archives; the other six remain missing.