Doctor: David Tennant (Tenth Doctor)
Companions: Catherine Tate (Donna Noble)
Billie Piper (Rose Tyler)
Freema Agyeman (Martha Jones)
John Barrowman (Jack Harkness)
Elisabeth Sladen (Sarah Jane Smith)
Noel Clarke (Mickey Smith)
Others
Camille Coduri – Jackie Tyler
Gareth David-Lloyd – Ianto Jones
Eve Myles – Gwen Cooper
Thomas Knight – Luke Smith
Bernard Cribbins – Wilfred Mott
Jacqueline King – Sylvia Noble
Adjoa Andoh – Francine Jones
Julian Bleach – Davros
Valda Aviks – German Woman
Shobu Kapoor – Scared Woman
Elizabeth Tan – Chinese Woman
Michael Price – Liberian Man
Nicholas Briggs – Dalek Voice
John Leeson – Voice of K9
Alexander Armstrong – Mr Smith[1]
Production
Directed by Graeme Harper
Written by Russell T Davies
Script editor Lindsey Alford
Produced by Phil Collinson
Executive producer(s) Russell T Davies
Julie Gardner
Incidental music composer Murray Gold
Production code 4.13
Series Series 4
Length 2nd of 2-part story, 65 minutes
Originally broadcast 5 July 2008
The episode continues from the end of "The Stolen Earth"; the Doctor (David Tennant) is regenerating inside the TARDIS. Once his body has healed, he halts the transformation by transferring the remaining energy into his severed hand (cut off during The Christmas Invasion). The TARDIS is captured by the Daleks and transported to the Crucible—the Dalek flagship. The Doctor and his previous companions Jack Harkness (John Barrowman) and Rose Tyler (Billie Piper) leave the TARDIS, but Donna Noble (Catherine Tate) is locked in. The Dalek Supreme orders the TARDIS to be destroyed; in the process, Donna collapses by the Doctor's severed hand. The energy stored in the hand forms a new Doctor who saves the TARDIS from destruction. Concurrently, Torchwood employees Gwen Cooper (Eve Myles) and Ianto Jones (Gareth David-Lloyd) find safety in an impenetrable time bubble; Sarah Jane Smith (Elisabeth Sladen) is saved from a Dalek extermination by Rose's ex-boyfriend Mickey Smith (Noel Clarke) and mother Jackie Tyler (Camille Coduri) and surrender themselves to get aboard the Crucible; Jack is killed and disposed of by the Daleks; and Martha Jones (Freema Agyeman) teleports to a castle near Nuremberg.
The Doctor and Rose are taken to Davros (Julian Bleach), creator of the Daleks. Davros explains that the twenty-seven stolen planets form a compression field which can cancel the electrical energy of atoms. The resulting "reality bomb" has the potential to destroy all matter in every universe; reality itself would be destroyed. After the device is tested, the Daleks receive two transmissions: Sarah, Mickey, Jack (who is revealed to be still alive), and Jackie threaten to destroy the Crucible using a "Warpstar" that Sarah Jane had, and Martha threatens to use the Osterhagen Key—a last resort device which would destroy Earth. Their actions cause Davros to challenge the Doctor's reliance on his companions and reminds him of the deaths that he had caused in the past.
Before either plan can be instigated, the Supreme Dalek has everyone transported to the Crucible and right in front of Davros. Davros prepares to detonate the reality bomb before the TARDIS materialises in front of him. The clone Doctor and then Donna try to use a device that will refocus the reality bomb onto the Daleks, but Davros blasts them both with electricity and destroys the device. This causes Donna to become imbued with Time Lord knowledge that she gained during the clone Doctor's creation, and she disables the reality bomb with seconds to spare. The two Doctors help her disable the Daleks and relocate the missing planets, but the control panel is destroyed before Earth can be relocated. Motivated by Dalek Caan's prophecy of the Daleks' extinction, the new Doctor destroys the Daleks and the Crucible. A shocked Davros is angered by Dalek Caan's betrayal. The original Doctor offers to save Davros who refuses, labeling the Doctor as "the Destroyer of Worlds" before he is killed by the ship's destruction. The companions flee into the TARDIS and "tow" the Earth back into its original orbit with the aid of Sarah's supercomputer Mr Smith, her robotic dog K9, and the spatio-temporal rift in Cardiff.
In the dénouement of the episode, the Doctor parts ways with his companions: Sarah returns home to her son Luke; Martha and Mickey leave with Jack; and the Doctor returns Rose and Jackie to the parallel universe they were trapped in, in "Doomsday". The Doctor has the other Doctor stay in the parallel universe for committing genocide and to requite Rose's love, since the second Doctor is part human. That means he has only one heart and can't regenerate, and will grow old and die along with Rose. After departing, Donna's human mind becomes overwhelmed by the Time Lord knowledge and starts to deteriorate. To save her life, the Doctor is forced to wipe her mind against her wishes, and explains to her mother, Sylvia (Jacqueline King), and grandfather Wilfred Mott (Bernard Cribbins) that Donna must never remember him or anything that they did otherwise she will die. As the Doctor leaves, Wilfred promises that he will never forget the Doctor on his granddaughter's behalf.
Journey's End