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As Captain Jack Harkness reappears in the Doctor's life, the TARDIS is thrown out of control to the end of the universe — where a lonely Professor is working on a means to save the remnants of humanity. But will the vicious Futurekind thwart his plans?
After landing in the year 100 trillion, on the planet Malcassairo, the Doctor, Jack, and Martha are surprised to find life - in the form of the Futurekind, mutated cannabalistic humans, hunting a human, who is aiming for a silo to travel to "Utopia" - the last home of the human race.
The Utopia project is headed by Professor Yana and his insectoid assistant Chantho, who are desperate for help as the rocket destined for Utopia is unable to take off. These problems are worsened by a Futurekind stowing away in the silo, who vandalises the controls to prevent take off. The Doctor and Jack volunteer to help - the Doctor helps Yana in his control room while Jack makes final preparations in a heavily irradiated room. While Jack is doing this, the Doctor talks to him about Jack's immortality, and why he abandoned him on Satellite Five. Finally, the rocket is able to take off, and does so to Utopia, leaving the Doctor, Yana, Chantho, Martha, and Jack on the planet's surface.
A subplot includes Yana hearing a constant drumbeat inside his head - a condition he has had since birth, with the drums getting louder recently. Words such as "regeneration" and "TARDIS" only exacerbate the problem. This is noticed by Martha, along with a watch of the exact same design as John Smith's watch in "Human Nature" and "The Family of Blood". She inquires about it - he had had it ever since he can remember. Subsequently, she immediately goes to inform the Doctor, which leaves Yana alone with the watch.
When the Doctor hears about this, he realises that the name "Yana" is an acronym of "You are not alone", the final words of the Face of Boe. At the same time, Yana opens the watch, releasing the Time Lord configuration. Suddenly angered and horrified, the Doctor races towards Yana's office, but is hindered by Yana closing the doors and allowing the Futurekind into the silo. Alone, Yana then fatally wounds Chantho, but not before telling her that he is the Master.
The Doctor arrives in Yana's office, but not before the Master enters the Doctor's TARDIS with the severed hand. Mortally wounded by Chantho, the Master regenerates into a younger body - whose voice Martha recognises. He then locks the TARDIS, preventing the Doctor from opening it, and after berating the Doctor, leaves in the TARDIS, stranding the Doctor, Martha and Jack in the distant future trapped by the Futurekind.
This is Derek Jacobi's third involvement in Doctor Who and second time playing the Doctor's nemesis. The first was in the September 2003 audio drama Deadline, where he played a screenwriter who believes himself to be the Doctor. The second was several months later, in the webcast Scream of the Shalka, where he played an android version of the Master. David Tennant also had a minor, uncredited role in Scream of the Shalka.
John Bell is a nine-year-old who won a Blue Peter competition to appear in this episode.
Continuity
Prior to this episode, Captain Jack was last seen at the end of the Torchwood episode "End of Days" looking off-screen while the familiar sound of the TARDIS is heard in the background. The Torchwood team find Jack gone, and the place in a mess. The Doctor notes that the Rift has been active recently, which was due to Abaddon escaping through the Rift in "End of Days".
Martha enquires about the earthquake in Cardiff a couple of years ago, and the Doctor claims "a bit of trouble with the Slitheen", referring to the events of the 2005 episode "Boom Town" He also states how he was "a different man back then" referring to the fact this happened when he was the Ninth Doctor.
Jack says that he used a Vortex Manipulator to travel back from the year 200,100. Vortex Manipulator technology was also used by the Family of Blood in "Human Nature" to track the Doctor through time.
Instead of landing in the 21st century, Jack found himself in 1869. This is the same year that the Rift is opened in Cardiff, as seen in "The Unquiet Dead".
One of the items in Jack's backpack was the severed hand of the Doctor. This was first seen in "The Christmas Invasion", when the hand was cut off by the Sycorax leader, and was a recurring item of the Torchwood Three Hub set. This Episode is the first confirmation that the Hand was in fact the Doctor's.
This episode contains clips from "The Parting of the Ways", "The Christmas Invasion", "Human Nature" and "Gridlock". It also features dialogue from The Daemons spoken by Roger Delgado, the first actor to play the Master, and the trademark chuckle of Anthony Ainley, who portrayed the character during the 1980s.
The Doctor previously claimed to be a "Doctor of Everything" in Spearhead from Space and described the human race as "indomitable" in The Ark in Space.
The last time the Master appeared on screen, he was in possession of a human host. How he survived being sucked into the TARDIS's Eye of Harmony at the end of the 1996 Doctor Who television movie or how he reacquired Time Lord physiology is not explained in this episode.
Derek Jacobi plays the fifth incarnation of the Master whom the Doctor has come across on screen, and John Simm is the sixth. At least one source had speculated whether "Mister Saxon" was an intentional anagram of "Master No. Six" or was perhaps "a big red herring". The Master often showed a penchant for disguise in the classic series, such as the name "Mr. Magister" in The Dæmons; the Professor's name 'Yana' is likely to have had to do with the fact that he was found on "The Shores of the Silver Devastation", the home of the Face of Boe, whose last words to the Doctor were the acronym Y.A.N.A., 'You Are Not Alone'.
Production and pre-broadcast publicity
This is the first episode of the series to feature John Barrowman's name in the opening credits, and the first time 3 people have been in the opening credits in the revived series.
Music cues originally composed for Torchwood are heard in the background of this episode, notably a variation of the Torchwood theme tune played when Jack runs torwards the TARDIS and a motif played when Jack lies dead having ridden on the TARDIS through the Vortex.
This episode was not announced to be part of a three-parter until the Totally Doctor Who episode the day before.
