The 'monster of the week' formula allows room for a Doctor Who spin: the zombies were being used to create cures for futuristic diseases, and the werewolf was an alien entity.
--The Doctor (David Tennant), in every episode
A new Doctor is in. Though a new Doctor Who is hardly news (the BBC series had eight between 1963 and 1989), the change doesn't usually happen so fast. When the BBC revived the character in 2005, Christopher Eccleston took the part. After only a few episodes aired, he pulled out. His last episode had the Doctor saving his companion, Rose Tyler (Billie Piper), but damaging himself critically in the process.
Because the Doctor is a man of numerous talents, amazing intellect, and measureless compassion -- not to mention the ability to regenerate when near death -- this damage didn't endanger his existence. He goes on and on, bouncing through space in his living ship, the Tardis (the name is an acronym for Time and Relative Dimensions in Space), which resembles a blue Police Box from mid-20th century London.
David Tennant's tour as the Tenth Doctor began on Christmas of 2005 in the UK (22 September in the U.S., on the SciFi Channel), with the special, "The Christmas Invasion." Rose returned to London on Christmas Eve with the new Doctor, who lapsed into a coma. While the Doctor spent most of the episode in his regenerative coma, he did wake for about 15 minutes at episode's end for an awkward swordfight against an invading alien leader. These few moments introduced the new Doctor's identity crisis. "I don't know what sort of man I am," he shouted, "Am I funny? Sarcastic? Moody?"
His questions were the focus of the Christmas special. No one knew who he was. As the previous Doctor, Eccleston had been dark and moody, given to sarcasm, driven by guilt. He was also genocidal, having ended a war, he believed, by killing the entire Dalek race. Throughout the 2005 season, Rose worked hard to recapture his original spirit and purpose, his love of life and of her. With the sudden recasting after Eccleston's unexpected departure, BBC was forced to refocus what had just been refocused.
The next two episodes, "New Earth" and "Tooth and Claw," showed a Doctor with both feet on the ground as Tennant and the show's writers had discovered the spirit of this new Doctor. Tennant's Doctor is more childlike and less self-aware (he asked Rose at one point if he was "being rude again"). Rose too has evolved. She's no longer just a passenger, but equal to the new Doctor, and their relationship has an even more pronounced romantic tension.
The new season's primary plot device has, so far, been monsters. "New Earth" involved zombies, "Tooth and Claw" featured werewolves. The "monster of the week" formula allows room for a Doctor Who spin: the zombies were being used to create cures for futuristic diseases, and the werewolf was an alien entity. The monsters also permit the continuation of thematic interests in prejudice and racism. Under Eccleston, that interest was connected to the West's ongoing battle with terrorism and the seemingly incompatible cultures of people immigrating to British shores. But the aliens have not been as terrible as human responses to them. The threat of "invasion" is often just a façade, and real threats are ignored.
Tennant's Doctor challenged the Prime Minister's (Penelope Wilton) use of a weapon of mass destruction in the name of "security" in "The Christmas Invasion." In "New Earth," Cassandra (Zoë Wanamaker), convinced that she was the only "pure" human left, referred to the rest of the human race as "mongrels" and "half-breeds." And in "Tooth and Claw," when Rose and the Doctor were transported to 19th Century Scotland, the Doctor himself was labeled a "threat" to the British Empire by Queen Victoria (Pauline Collins).
This theme -- fear of others -- resonates in the U.S. as well the UK, for obvious reasons. Authorities on Doctor Who have committed murder in the name of security, remained willfully blind to real dangers, and retaliated against those who question their motives. Having begun in the 1960s as an educational program, Doctor Who still attempts to "educate" its audience. In the past, this effort took the form of "history lessons": kids learned about the past by watching the quirky Doctor's travels. Now Doctor Who is not only looking at how things were, but also at how they are, using the lens of history to gain perspective on the present.
The Doctor has long been an observer and judge of "humanity." Because of his objectivity and dislocation, he's something of an anthropologist, trying to make sense of human cultures (granted, the series remains rooted in Western culture, with a familiar framework of values and beliefs). Doctor Who presents worlds and moments that seem full of problems, allowing viewers to believe there is time enough to solve them.