Doctor Who (series 1) Eccleston as the ninth incarnation of the Doctor, his only series in the role, accompanied by Billie Piper, as his first and main companion Rose Tyler, whom he plucks from obscurity on planet Earth, and to whom he grows increasingly attached. He also travels briefly with unruly boy-genius Adam Mitchell, played by Bruno Langley, and with 51st-century con man and former "Time Agent" Captain Jack Harkness, portrayed by John Barrowman. Episodes in the series form a loose story arc, based upon the recurring phrase "Bad Wolf", the significance of which goes unexplained until the two-part series finale. Alongside the "Bad
Time War (Doctor Who) their demise, the paths between worlds are now closed. The Time Lords could also prevent or repair paradoxes such as the one created by Rose in an attempt to save her father's life in a traffic accident. After the Time Lords' disappearance, such a paradox summons the Reapers, who descended to "sterilise the wound" in time by devouring everything in sight, and are only stopped by Pete Tyler killing himself. Because of the Time Lock, along with the danger of creating a paradox, the Doctor is prevented from going back in time and saving the Time Lords. The Tenth Doctor