“The Poison Sky” is the fifth episode of the fourth series (since revival) of British science fiction television series Doctor Who. It was broadcast on BBC One on 3 May 2008. The episode features both old companion Martha Jones and the alien Sontarans. It is the second of a two part story, following “The Sontaran Stratagem”.
Plot
Synopsis
Following from the previous episode, Sylvia Noble (Jacqueline King) manages to free Wilfred Mott (Bernard Cribbins) from the car by smashing the window with an axe. The Doctor (David Tennant) sends Donna Noble (Catherine Tate) back to the TARDIS while he sets off to figure out what the Sontarans are up to. After studying the gas, UNIT determines that it will need to reach 80% density to become lethal. Elsewhere, Martha Jones’s clone (Freema Agyeman) informs the Sontarans of UNIT’s defence systems and helps them to teleport the TARDIS to their orbiting ship. Realising that he is trapped, the Doctor attempts to goad General Staal (Christopher Ryan) into revealing their plan: Staal is smart enough not to fall prey to this ploy, but the Doctor soon works out by himself that the Sontarans plan to use the Earth for their own benefit, since they are beginning to lose their long war with the Rutans. He also tricks Staal into moving 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 weapons against the Sontarans; however, Martha’s clone has covertly copied the launch codes, and stops every attempt they make to fire the weapons. This in itself shows a hidden agenda, since the Doctor knows a nuclear strike would not have harmed the Sontarans in the first place. This, combined with the unidentifiable elements in the gas, suggest that the Sontarans have an interest in keeping anything from disrupting the atmospheric conversion. At the same time, the Sontarans, under Commander Skorr “the Bloodbringer” (Dan Starkey), mobilize a contingent of troops to protect the factory. With the Sontarans’ ability to jam most conventional firearms by expanding the copper-lined bullets, the UNIT troops are quickly slaughtered and the factory is secured.
Luke Rattigan (Ryan Sampson) leaves the Sontaran mothership to gather his students, explaining that he plans to have the Sontarans take them to another planet and begin the human race anew. The students merely laugh him off, even when he brandishes a gun. When he returns to report his failure, the Sontarans likewise ridicule his efforts, admitting that they had planned to kill his students and never intended to take him anywhere. Rattigan teleports back to his mansion before they can kill him, and the Sontarans lock the teleport pods behind him. Back in his own quarters, he lies sobbing on the ground.
Meanwhile, the Doctor instructs Donna on how to reopen the teleport pods. As she makes her way through the ship, UNIT begins a counterattack, loading their weapons with non-copper bullets and using the aircraft carrier Valiant to clear the gas. The counterattack is a success, and the UNIT troops are able to put the Sontarans on the defensive. The distraction allows the Doctor to make his way to the cloning room where Martha is being held. Having figured out long before that 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, and the clone reveals that the poison gas is actually food for Sontaran clones: they are converting the planet into a giant breeding world. With Donna’s help, the Doctor is able to reactivate the teleport pods, allowing him to rescue Donna, steal back the TARDIS, and teleport into Rattigan’s mansion.
With the terraforming equipment Rattigan’s students built, the Doctor builds his own atmospheric converter, igniting the atmosphere to clear out the poison gas as shown in the picture. However, he knows the Sontarans won’t accept defeat so easily, and teleports to their ship with the converter, planning to give them the choice between retreat or death. Staal chooses the latter, content with the knowledge that the Doctor will die with them. At the last moment, Rattigan teleports himself to the Sontaran ship and sends the Doctor back to Earth, sacrificing himself to destroy the Sontarans.
With the day saved, Martha says goodbye to Donna and the Doctor in the TARDIS and prepares to head home. However, before she can leave, the TARDIS suddenly springs to life, locking the doors and piloting itself to an unknown destination as the jar containing the Doctor’s severed hand bubbles.
Continuity
- Brigadier Lethbridge-Stewart is mentioned as being “stranded in Peru”, the first explicit mention of the character in the new series. Colonel Mace refers to him as “Sir Alistair”, implying he has received a knighthood since the events of Battlefield.
- Just as Donna moves towards the TARDIS screen while the Doctor contacts the Sontarans, Rose Tyler briefly appears on the screen, silently calling out. This follows a similar silent cameo appearance in “Partners in Crime”. The same happens in “Midnight.”
- The Valiant, the primary setting for the climax of “The Sound of Drums” and much of “Last of the Time Lords”, is seen again in this episode when it is used by UNIT to clear the poisonous gas from the atmosphere over the ATMOS factory. It is also equipped with a scaled down version of the Torchwood weapon that destroyed the Sycorax ship in “The Christmas Invasion”.
- As the TARDIS traps Donna, Martha, and the Doctor at the end of the episode, the Doctor’s severed hand, last seen at the beginning of “Voyage of the Damned”, can be seen in a similar state of agitation it felt when the TARDIS materialised near it in the Torchwood episode “End of Days”.
- In addition to the Sontarans, the Rutans are mentioned for the first time in the revived series.
- Lachele Carl reprises her recurring role as Trinity Wells, a US newsreader, seen previously in the episodes “Aliens of London”, “World War Three”, “The Christmas Invasion” and “The Sound of Drums” and in Doctor Who spin-off The Sarah Jane Adventures story Revenge of the Slitheen.
- The Doctor asks Colonel Mace, “Are you my mummy?”, while wearing a gas mask – a line spoken by gas mask-wearing characters in “The Empty Child” / “The Doctor Dances”.
- The episode is revisited in the series four episode “Turn Left”, where Jack Harkness and the remaining Torchwood team of Gwen Cooper and Ianto Jones stop the Sontarans in a parallel timeline. Harkness is transported to Sontar while Cooper and Jones are killed destroying the Sontaran ship.
- The finale episode “Journey’s End” features a brief flashback of Luke’s sacrifice, among others, as the Doctor remembers all of those who have died for him.
- The Doctor doubles back from calling Martha, Donna, and himself the “old team”, and calls them the “new team”. In Series 2’s “Doomsday”, Rose proclaims that the Doctor and herself are the “old team”.
- A single remaining Sontaran from this story is the focus of The Sarah Jane Adventures story “The Last Sontaran”.
Production
This episode and the previous episode were filmed over five weeks, beginning in September 2007. Post-production was completed a week before the first part aired.
During production, director Douglas Mackinnon intended to have the episode’s climatic scene in the TARDIS show the moveable column in the center console move up and down much more rapidly than normal. However, when attempting to accomplish this, Mackinnon ended up breaking the prop, which took thirty minutes to repair.
When interviewed on Friday Night with Jonathan Ross, Catherine Tate stated that she had been filming alongside ten actors playing Sontarans for two weeks before she realised that there were actors inside the Sontaran costumes. She had assumed the Sontarans “ran on electricity”. It was not until an actor removed his helmet to reveal his real face that she realised her mistake. She stated she was “freaked out” by this and said she “nearly died”.
When the Doctor interrupts the Sontarans’ transmission, animated footage from CBeebies’s part live action, part animationeco adventure show Tommy Zoom is brought up on screen featuring the villanous Polluto disguised as a magician and the heroic Tommy and his dog Daniel as his audience. Originally, the plan was to use Shaun the Sheep, but this fell through.
As in many previous episodes of the revived series, supposed BBC News 24 footage is used featuring reports of unfolding events. However, as with the more recent appearances of such footage in Doctor Who, the channel is simply captioned on screen as ‘News 24′ devoid of the BBC logo. Since this episode was produced, the BBC News 24 channel was rebranded in real life as BBC News.
Broadcast
Unofficial overnight figures indicated that “The Poison Sky” was watched by 5.9 million viewers, giving it a 32.5% share of the total television audience. The final consolidated figure was 6.53 million viewers. It was the second most watched programme of the day, being beaten by ITV1’s Britain’s Got Talent, which got 9.12 million viewers. It was the highest rated programme on BBC1 for the day and the 18th most watched of the week. The episode received an Appreciation Index score of 88 (considered “Excellent”).
