The second series of British science fiction programme Doctor Who began on 25 December 2005 with the Christmas special "The Christmas Invasion". Following the special, a regular series of thirteen episodes was broadcast, starting with "New Earth" on 15 April 2006. In addition, two short special episodes were produced; a Children in Need special and an interactive episode, as well as 13 TARDISODEs. It is the second series of the revival of the show, and the twenty-eighth season overall. This is the first series to feature David Tennant as the tenth incarnation of the Doctor, an alien Time Lord who travels through time and space in his TARDIS, which appears to be a British police box on the outside. He continues to travel with his companion Rose Tyler (Billie Piper), with whom he has grown increasingly attached. They also briefly travel with Rose's boyfriend Mickey Smith (Noel Clarke), and Camille Coduri reprises her role as Rose's mother Jackie. The series is connected by a loose story arc consisting of the recurring word "Torchwood". This is also the first series to be preceded by a Christmas special, which was commissioned to see how well the show could do at Christmas. The success of "The Christmas Invasion" led to the Christmas special becoming an annual tradition. From Wikipedia
