The Doctor (Doctor Who) Time Lords a fixed number of twelve regenerations, meaning that every Time Lord had a total of thirteen incarnations including the original. The plot of "The Time of the Doctor" involves the Doctor receiving a new cycle of regenerations from the Time Lords before his expected demise, triggering the regeneration into the Twelfth Doctor, played by Peter Capaldi. The origins of the programme were explored in the docudrama "An Adventure in Space and Time" as part of the 50th anniversary celebrations of "Doctor Who", which starred David Bradley as William Hartnell. Although Time Lords resemble humans, their physiology differs in
Partners in Crime (Doctor Who) Partners in Crime (Doctor Who) "Partners in Crime" is the first episode of the fourth series of the British science fiction television series "Doctor Who". It was broadcast on BBC One on 5 April 2008. The episode reintroduced actor and comedian Catherine Tate as the temp Donna Noble, who had previously appeared in the 2006 Christmas Special "The Runaway Bride". In the episode, Donna and the alien time traveller the Tenth Doctor (David Tennant) meet while separately investigating Adipose Industries, a company that has created a revolutionary diet pill. Together, they attempt to stop the death of thousands of people