Editing The Poison Sky (TV story)

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{{Infobox Story
|image = poisonsky.png
|name = The Poison Sky
|series =[[Doctor Who television stories|''Doctor Who'' television stories]]
|season number = [[Series 4 (Doctor Who)|Series 4]]
|story number = 192b
|doctor = Tenth Doctor
|companions = [[Donna Noble|Donna]],[[Martha Jones|Martha]]
|enemy = [[Sontaran]]s, [[Martha Jones (clone)|Clone facsimile]], [[Luke Rattigan]](redeems himself)
|setting = {{il|[[London]], [[2009]]|[[Rattigan Academy]], [[2009]]|[[Sontaran flagship]], [[2009]]}}
|writer = [[Helen Raynor]]
|director = [[Douglas Mackinnon]]
|producer = [[Susie Liggat]]
|confidential=[[Sontar-Ha!]]
|broadcast date = [[3 May (releases)|3 May]] [[2008]]
|network=[[BBC One]]
|format = 1 45 minute episode
|production code = 4.5
|prev = The Sontaran Stratagem (TV story)
|next = The Doctor's Daughter (TV story)
}}
'''''The Poison Sky''''' was the fifth episode of the [[Series 4 (Doctor Who)|fourth series]] of ''[[Doctor Who]].'' Unlike other episodes of the season, this one had no reference to the Missing Planets Arc. It saw the Doctor's life saved again by and at the cost of the life of another person. 

This episode left a loose end about the Sontarans' defeat that was used in ''[[The Sarah Jane Adventures]]'' episode ''[[The Last Sontaran]]''. 

== Synopsis ==
As the gas from the [[Tenth Sontaran Battle Fleet]]'s [[Atmospheric Omission System|ATMOS]]' continues to thicken throughout the world, a [[Martha Jones (clone)|clone of Martha Jones]] works in the shadows to support them. Will the Doctor learn about Martha's replacement? And can he figure out what the gas is made of and destroy it before the entire planet chokes to death or [[UNIT]] accidentally initiates an interplanetary war with the Sontarans in their bid to be rid of the gas?

== Plot ==
[[Tenth Doctor|The Doctor]] continues [[Sonic screwdriver|sonicking]] the car in his attempt to free [[Wilfred Mott|Wilf]] from it before he chokes on the [[Sezerfine gas|gas]]. However, it proves useless as [[Sylvia Noble|Sylvia]] frees Wilf from the car by smashing the window with an [[axe]] she keeps in case of burglars. [[Ross Jenkins|Ross]] arrives in a [[taxi]], the only thing he could find not fitted with ATMOS. Despite Sylvia's protests, Donna goes with the Doctor back to the [[ATMOS factory]] with her grandfather's support. 

Arriving at the factory, the Doctor gives [[Donna Noble|Donna]] a [[TARDIS key|key]] to [[The Doctor's TARDIS|the TARDIS]] so she can wait without choking on the air. Donna manages to enter the TARDIS just as she began coughing hard from the gas. In the meantime, [[Martha Jones (clone)|Clone Martha]] overhears a [[Radio transmitter|radio transmission]] of the Doctor's arrival and tells [[Mace|Colonel Mace]] the previous message the Doctor gave her: [[Code Red]] Sontaran. Rushing into the mobile base, the Doctor tells Mace not to engage the Sontarans in battle. When questioned what he plans to do, the Doctor says he'll use the TARDIS to get on their [[Sontaran flagship|ship]] to talk with them.

Clone Martha subtly gives orders to the [[Hypnosis|hypnotised]] [[UNIT]] soldiers [[Carl Harris|Harris]] and [[Steve Gray|Gray]] to put [[teleport relays]] on the TARDIS for the Sontarans to beam it up. Once done, Donna feels a shake from the teleport. The Sontarans gloat over having the Doctor's infamous vessel. The Doctor and Clone Martha arrive to find the TARDIS gone. Knowing he is trapped, the Doctor tries to goad the Sontarans into revealing their plan. The Sontarans do not to fall prey to this ploy, but they move the TARDIS out of the main war room, placing Donna in a position to help.

Against the Doctor's advice, UNIT decides to use [[Nuclear weapon|nuclear weapons]] against the Sontarans; however, Martha's clone has covertly copied the [[Launch code|launch codes]], and stops every attempt they make to fire the weapons. The Sontarans mobilise troops to retrieve and protect the clone. With the Sontarans' ability to jam most conventional [[Firearm|firearms]] by expanding the [[copper]]-lined [[Bullet|bullets]], the UNIT troops are quickly slaughtered and the factory is secured.

[[Luke Rattigan|Rattigan]] leaves the Sontaran flagship to gather his students. He plans to take them to another planet and begin the human race anew. The students laugh him off, even when he brandishes a gun. When he returns to report his failure, the Sontarans too ridicule his efforts, having never planned to take him. Rattigan [[Teleportation|teleports]] back to his [[Rattigan Academy|mansion]] before they can kill him, and the Sontarans lock the [[Teleport pod|teleport pods]] against him.

[[File:The Poison Sky Tenth Gas Mask Mommy.JPG|thumb|left|"Are you my mummy ?"]]Meanwhile, the Doctor instructs Donna to reopen the teleport pods. UNIT uses the ''[[Valiant (aircraft carrier)|Valiant's]]'' turbofan engines to clear an area around the factory. A [[Jathaa sunglider|Sunglider]] weapon - smaller than that used against the [[Sycorax]] - is their main offence and with steel-encased bullets in lieu of copper, they begin a successful retaliatory strike.

The Doctor makes his way to the cloning room where Martha is being held. Having figured out long before the clone wasn't the genuine article, he severs its connection to Martha, leaving it to die. Martha convinces the clone to betray the Sontarans in its last moments. The clone reveals that the poison gas is actually "[[Clone Feed|clone feed]]" for Sontaran clones: they are converting the planet into a giant breeding world. With Donna's help, the Doctor reactivates the teleport pods, rescues Donna, steals back the TARDIS, and teleports into Rattigan's mansion.

With Rattigan's equipment, the Doctor builds an [[atmospheric converter]], igniting the [[atmosphere]] to clear out the poison gas. However, he knows the Sontarans won't accept defeat so easily - they are beginning their standard invasion stratagem. He tells Donna and Martha to lead good lives, tells Rattigan to go on and do something clever, and teleports to their ship with the converter to give them the choice between retreat and death. The Sontarans choose the latter, but the Doctor cannot bring himself to destroy a ship full of sentients. However, with a few seconds left, Rattigan simultaneously teleports himself to the Sontaran ship and the Doctor back to Earth. The Sontarans stop their "[[haka]]" with the new development. Luke says "Sontar? Ha!" and detonates the device.

With the day saved, the Doctor and Donna say their goodbyes to Martha, only to have the TARDIS spring to life and begin piloting itself to places unknown before she can leave, the Doctor's [[The Tenth Doctor's hand|hand jar]] bubbling...

== Cast ==
* [[Tenth Doctor|The Doctor]] - [[David Tennant]]
* [[Donna Noble]] - [[Catherine Tate]]
* [[Martha Jones]] - [[Freema Agyeman]]
* [[Rose Tyler]] - [[Billie Piper]]
* [[Wilfred Mott]] - [[Bernard Cribbins]]
* [[Sylvia Noble]] - [[Jacqueline King]]
* [[Staal|General Staal]] - [[Christopher Ryan]]
* [[Skorr|Commander Skorr]]/[[Skree|Lieutenant Skree]] - [[Dan Starkey]]
* [[Alan Mace|Colonel Mace]] - [[Rupert Holliday Evans]]
* [[Luke Rattigan]] - [[Ryan Sampson]]
* [[Ross Jenkins]] - [[Christian Cooke]]
* [[Marion Price|Captain Price]] - [[Biddy Hodson]] (credited as "Bridget Hodgson")
* [[Harris (The Sontaran Stratagem)|Private Harris]] - [[Clive Standen]]
* [[Steve Gray|Private Gray]] - [[Wesley Theobald]]
* [[Newsreader (The Poison Sky)|Herself]] - [[Kirsty Wark]]
* [[Trinity Wells]] - [[Lachele Carl]]

== Production crew ==

* Uncredited: [[Alice Troughton]] (director, [[Billie Piper]] sequence, used again in [[TV]]: ''[[Midnight]]'')

== References ==
* The Doctor mentions the [[Rutan Host|Rutans]] and the [[Rutan-Sontaran War]].
* The [[Alistair Gordon Lethbridge-Stewart|Brigadier]] is said to be stranded in [[Peru]]. He has been knighted as Colonel [[Alan Mace|Mace]] refers to him as "Sir Alistair". This is the first reference to the character in ''Doctor Who'' since the 1989 story ''[[Battlefield]]'', although several references occurred in the first season of ''[[The Sarah Jane Adventures]]'', broadcast in 2007. The Brigadier was knighted in the book [[PROSE]]: ''[[The Dying Days]]'' and called "Sir Alastair" in [[Big Finish Productions]]' audio dramas. The Doctor wishes he was there.
* The Doctor asks, "Are you my mummy?" while wearing a gas mask like the [[Jamie (The Empty Child)|Empty Child]] from [[TV]]: ''[[The Empty Child]]''.
* The Doctor addresses the Sontarans "under [[Jurisdiction Two]] of the [[Intergalactic rules of engagement]]" which is very similar to the [[Shadow Proclamation]].
* The Doctor watches ''Tommy Zoom'' while waiting for the Sontarans to stop chanting. This is similar to [[the Master]] watching other shows such as ''[[Teletubbies]]'' and ''[[The Clangers]]''.
* UNIT uses the ''[[Valiant (aircraft carrier)|Valiant]]'' to blow away ATMOS' gases. When the Doctor admires the ship and Colonel Mace asks if he has a taste for it, the Doctor is quick to reply, "Not at all. Not me." This can be interpreted as masked reluctance from the Doctor to acknowledge any similarities between himself and the Master, who was very keen on the ''Valiant''. Most likely, though, it was simply the Doctor reacting to the unpleasant memories of his [[Year That Never Was|year spent in captivity]] aboard the vessel.
* The Valiant's laser is similar to that of [[Torchwood 1]] one used against the [[Sycorax]], which in turn was very similar to the Death Star's laser from the ''[[Star Wars]]'' movies. ([[TV]]:''[[The Christmas Invasion]]'')
* During the pollution crisis the American newsreader mentions that it is the "end of days" which was also said after [[Owen Harper|Owen]] opens the [[Cardiff Rift|rift]] and caused shockwaves around the world. ([[TV]]:''[[End of Days]]'')
* The Doctor mentions [[Jack Harkness]] when he confronts the Martha clone.
* Luke Rattigan believed the Sontarans would take him and his followers to Castor 36, a planet orbiting [[Alpha Geminorum]].
* The close-up of the news reader's eyes and mouth are reminiscent of the Doctor's message during ''[[Blink]]''.
* The scene in which Luke Rattigan beams to the Sontaran ship to swap places with the Doctor is similar to the scene in ''Star Trek: Nemesis'' in which Lt Commander Data beamed Cpt Jean-Luc Picard away from the Scimitar before it exploded, causing his own death.

== Story notes ==
* [[Helen Raynor]] wrote this episode. Her [[Series 3 (Doctor Who)|Series 3]] episodes ''[[Daleks in Manhattan]]'' and ''[[Evolution of the Daleks]]'' both occupied fourth and fifth episode in the series. This two part episode also occupies episode four and five.
* This the second part of a story which began with ''[[The Sontaran Stratagem]]''.
* This story and ''[[The Sontaran Stratagem]]'' are [[Douglas Mackinnon]]'s first stories as director.
* When the Doctor cuts off Staal's speech on the video screen in mid flow, a clip from [[Wikipedia:CBeebies|CBeebies]] cartoon ''[[Wikipedia:Tommy Zoom|Tommy Zoom]]'' is featured. The original plan to use a clip from ''[[Wikipedia:Shaun the Sheep|Shaun the Sheep]]'' fell through.
* [[Billie Piper]] appears very briefly as [[Rose Tyler]] on the TARDIS's screen in this episode. She receives screen credit, and is fourth-billed, for a performance that lasts less than one second and which was actually shot for another episode.
* According to [[Russell T Davies]] in an interview in [[DWM 396]], the cameo by Rose was not in the original edit of the episode, but was added just before broadcast when Davies learned how successful her unbilled cameo in ''[[Partners in Crime]]'' was. Although it was reported that the clip came from "an untransmitted scene" from another episode, in fact, according to the DVD commentary for ''[[Midnight]]'', the scene was shot especially for ''Midnight'' during production of ''[[Turn Left]]'' and Davies dropped the scene into ''The Poison Sky'', too. Davies said that, like ''Partners in Crime'', advance review copies of this episode did not include the cameo. This scene was directed by [[Alice Troughton]].
* The music that plays when the ''Valiant'' appears is strikingly similar to "The Master Tape", one of the Murray Gold themes for the Master. The Master helped design the ''Valiant''.
* When Martha Jones wears the Doctor's jacket at the end of the episode, she says she feels like "a kid in my Dad's clothes." The following episode features an actual daughter of the Doctor.
* This is the first episode to feature [[Billie Piper]], [[Freema Agyeman]], and [[Catherine Tate]] all together as [[Rose Tyler|Rose]], [[Martha Jones|Martha]], and [[Donna Noble|Donna]], respectively. It is not, however, the first ''story ''in which all three ''actresses ''appear, as all three appear in ''[[Army of Ghosts]]/[[Doomsday]]. ''
* The Doctor says to the clone Martha "Avanti", which is "Let's go" in Italian. This is probably to confirm his suspicion of her clone nature. The real Martha would know that the Doctor usually says "Allons-y" which is "Let's go" in French.
* As is routine for post-2005 ''Doctor Who'', a "NEXT TIME" trailer for the [[The Doctor's Daughter|next episode]] is shown at the end of the episode.

=== Ratings ===
* 6.5 million viewers

=== Myths and Rumours ===
* Billie Piper's brief cameo was taken from an earlier episode, most likely ''[[The Idiot's Lantern]]'' in which she was also shown shouting silently from a TV screen. ''In fact, the scene was filmed especially for ''[[Midnight (TV story)|Midnight]]'', and inserted into this episode at the last minute.''

=== Filming locations ===
==== Studio ====
* Upper Boat Studios, Trefforest
* BBC Broadcasting House, Llandaff

==== Location ====
* Margam Country Park, Port Talbot
* Usk Valley Business Park, Pontypool
* Nant Fawr Road, Cardiff
* Orion Electric, Port Talbort
* Roath Basin, Cardiff Docks

=== Production errors ===
{{discontinuity}}
* When Martha's clone enters the mobile HQ, it can be seen that she entered through a normal building's door (with daylight coming in through the window) which isn't present on the back of the vehicle or in the previous episode.
* During the end we see the Sontaran's weapons starting to target the Earth. They get ready and open up, yet when it's destroyed, they're still closed.
* During the warehouse battle, around when the Doctor tells Donna, "Hold on, I'm coming", the film crew can be seen reflected in a door at the right of screen.
* When Colonel Mace confronts Commander Skorr, he raises his gun twice: once in one shot, and immediately after in the other.
* When the atmospheric converter began burning the sky, it is seen that the fire sweeps from the dark side of the earth towards the light side. The same could be seen when the fire recinds. The fire should be sweeping from the light side towards the dark side, as the conversion began in London UK during the daytime, and recinded from the same location.
* Near the end when Luke Rattigan teleports onto the Sontaran ship, he catches the detonation device, then catches it again in a close up.

== Continuity ==
* Sontaran High Command was mentioned in [[TV]]: ''[[The Two Doctors]]''.
* The ''Valiant'' last appeared in [[TV]]: ''[[Last of the Time Lords]]''.
* At the end of the episode, when the TARDIS flies off, the Doctor says his "What?! What?! What?!" line from Donna's first appearance in [[TV]]: ''[[The Runaway Bride]]'' and also from ''The Voyage of the Damned'' when the Titanic smashed through the TARDIS.
* Rose Tyler appears on the TARDIS scanner screen for a split second. She appears to be shouting, "Doctor!" and was last seen in [[TV]]: ''[[Partners in Crime]]''. This is not the first time Rose has attempted to communicate with the Doctor though a television screen, as she also attempted this in [[TV]]: ''[[The Idiot's Lantern]]''.
* After the Sontarans fill the area with gas, the Doctor wears a gas mask. While being shown a gun by Colonel Mace, he is asked what he thinks. His reply is, "Are you my mummy?", a reference to the episodes ''[[The Empty Child]]'' and ''[[The Doctor Dances]]'', in which the child asks this question numerous times. It is worth noting that these episodes did not feature David Tennant as the Doctor, but instead Christopher Eccleston as the [[Ninth Doctor]].
* The ''Valiant's'' laser appears to be the same that Torchwood used in [[TV]]: ''[[The Christmas Invasion]]'' (''Similar, not the same - this one's much smaller'').
* The Doctor thanks Donna and Martha just before he tries to sacrifice his life. He last said this to Donna in [[TV]]: ''[[The Sontaran Stratagem]]'' when she was supposedly leaving him.
* In the New York scene a building with the name "[[Butler Institute]]" can be seen on one of the buildings. The Butler Institute first appeared in [[PROSE]]: ''[[Cat's Cradle: Warhead]]''.
* Gas was released over [[London]] previously in [[PROSE]]: ''[[Amorality Tale]]''.
* The Doctor gave clues to Donna about what action to take via a visual link, but the Sontarans didn't know it was happening. The Doctor did a similar thing in [[TV]]: ''[[The Age of Steel]]'', when he gave clues to [[Mickey Smith|Mickey]] about how to stop the [[Cyberman (Pete's World)|Cybermen created by Cybus Industries]].
* In [[TV]]: ''[[Turn Left]]'', the Sontaran invasion was stopped by Torchwood 3. The atmosphere was reverted to its previous state and the Sontaran flagship exploded by [[Gwen Cooper]] and [[Ianto Jones]]. [[Jack Harkness]] was stranded on [[Sontar|the Sontaran's home planet]].
* The destruction of the Sontaran ship will be shown again in [[TV]]: ''[[The Last Sontaran]]''.
* When the Doctor yells at Colonel Mace, David Tennant's gold tooth can be visibly seen. This became the subject of an internet meme wondering if the Doctor regenerated them or if he has practised lacklustre dental hygiene in his tenth incarnation's relatively short life and, that being the case, chastising him.

== Home video releases ==
[[File:Series-4-volume-3.jpg|thumb]]
* This story was released in the [[Series 4 (Doctor Who)|Series 4]] DVD box set in [[November]] [[2008]] along with the rest of the series.
* It was released as Series 4 Volume 2 in a vanilla edition with ''[[The Sontaran Stratagem]]'', ''[[The Doctor's Daughter]]'' and ''[[The Unicorn and the Wasp]]''.

== External links ==
* [http://www.bbc.co.uk/doctorwho/s4/episodes/S4_05 Official BBC Website - Episode Guide for '''The Poison Sky''']

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[[Category:Doctor Who (2005) television stories]]
[[Category:Tenth Doctor television stories]]
[[Category:UNIT television stories]]
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[[Category:Stories set in 2009]]
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[[Category:Series 4 (Doctor Who) stories]]
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[[Category:Missing Planets arc]]