[[caption-width-right:350:[[TheNthDoctor No,]] Creator/TomBaker isn't the solution to the problem, ''put the gun '''down'''''.]]
-> ''You don't understand. No-one who didn't live through those terrible years can understand. Towards the end of the 20th Century, a series of wars broke out. There were hundreds of years of nothing but destruction and killing. Nearly seven eighths of the world's population wiped out. The rest living in holes in the ground, starving, almost reduced to the level of animals...''
-->-- '''The Controller''' tries to justify collaborating with the Daleks.

Before ''Film/TheTerminator'', there was "Day of the Daleks".

A peace conference is being held in Britain under the auspices of Sir Reginald Styles - it's a reconvening of the one from "[[Recap/DoctorWhoS8E2TheMindOfEvil The Mind of Evil]]", and UNIT are once again providing security.

Styles is attacked and nearly killed by a guerrilla fighter in futuristic dress, but is saved by the intervention of a big - well - '''go'''rilla fighter, who knocks the assassin out and disappears. The Doctor deduces that the unconscious man is from the future, and that a device found with him is a time-travel gadget.

The Doctor poses as Styles in order to catch the assailants. They try again, but the Doctor convinces them he's not Styles. Jo accidentally activates one of the time-travel gadgets and zaps herself into the 22nd century, and the Doctor and the guerrillas follow her. One of the guerrillas, Shura, is attacked and left behind, presumed dead.

We discover that in this future, the Earth is ruled by the Daleks, using their ape-like Ogron subjects as heavies. There are also human collaborators, led by "the Controller". Jo and the Doctor are taken prisoner at the Dalek base, but rescued by the guerrillas - who finally get round to explaining that they're trying to kill Styles because they believe he blew up the peace conference, which started a series of wars leaving Earth shattered and ripe for Dalek conquest. They mean to kill Styles first and change "history".

The Doctor realises that this is a StableTimeLoop - that the explosion was actually caused by the guerrillas: specifically by Shura, the injured man left behind in the 20th century, trying to fulfill his mission. He gets back to the 20th century in time to have Styles' house evacuated and the pursuing Daleks and Ogrons are destroyed when Shura detonates his bomb.

* AlternateHistory: The Doctor visits a future Earth which he then retrospectively turns into an alternate history. To elaborate, just after the Doctor left our time, WorldWarIII broke out, weakening Earth and enabling the Daleks to take over. The Doctor learns enough about how the war started to return to our time and prevent it from happening, thus erasing the Dalek-occupied future.
* AllThereInTheScript: Dialogue cut from the script established that all the Daleks infected with the Human Factor at the climax of "[[Recap/DoctorWhoS4E9TheEvilOfTheDaleks The Evil Of The Daleks]]" had been eradicated, indicating that that story was not the “final end” of the Daleks after all.
* AnAstralProjectionNotAGhost: The ghosts the Doctor is asked to investigate turn out to be projections of time travellers from the future.
* BadFuture: So bad that some people thought that occupation by the Daleks was an ''improvement''.
* BatmanGrabsAGun: The Doctor disintegrates an Ogron with a laser gun.
* BoundAndGagged: This is the ONLY serial in the entire run of ''Series/DoctorWho'' where both the Doctor and his companion (Jo Grant) are bound and gagged.
* BridgeBunnies: All the Controller's technicians are blonde young women.
* ContinuityCavalcade: Images of the previous Doctors appear on the Daleks' monitor screen as they interrogate him.
* ContinuityNod: [[Recap/DoctorWhoS8E2TheMindOfEvil This is the second time UNIT has provided security for a peace conference (and once more the problem is due to the Chinese)]].
* CrapsackWorld: Future version of Earth, ruled by Daleks
* DeceptionNoncompliance: The Doctor is held prisoner and then required to reassure {{the Brigadier}} that all is well over the telephone. He finds a subtle way to secretly call for help:
-->''"I assure you, Brigadier, there's nothing to worry about. Tell Styles that. Tell the Prime Minister. And, Brigadier, be particularly sure to tell it to the Marines."''
* DisintegratorRay: The guns used by the Ogrons and the Guerrillas.
* DyingMomentOfAwesome: The Controller helps the Doctor and Jo return to the past to try and stop the Daleks' world domination scheme, but stays behind to confront his masters.
* EnhancedOnDVD: The DVD special release does an ''extensive'' overhaul of the episode. It adds a lot of CGI in place of the primitive green screen-esque colour separation overlay effects (the monitors look more futuristic, the Dalek headquarters exterior shot is completely different and the building looks more intimidating with flying vehicles in the background), laser blasts, with people and Ogrons being more graphically disintegrated (controversially adding a scene where the Doctor [[BatmanGrabsAGun kills another Ogron]]). It also has veteran Dalek voice actor Creator/NicholasBriggs portray the Daleks in place of the original and admittedly shaky voice acting. (The series had tried to write off the Daleks and thus didn't have a go-to actor portrayal ready and able, and so the producers brought on two actors, Oliver Gilbert and Peter Messaline, who hadn't been as versed with Dalek voices and by now were out of practice. Neither Messaline nor Gilbert had ever been featured in ''any'' Doctor Who media before, nor since. Roy Skelton would later be called back (alongside future Davros actor Michael Wisher) and become the definitive classic series' voice of the Daleks.) Most notably, the climactic battle at Auderly House had entire sequences re-filmed ''decades'' after the serial had been released through funding by 2 entertain to show a true army of Daleks and Ogrons duking it out versus using new and borrowed costumes, when the original tried to create the illusion of an army by re-using the same shots of only a few Daleks and Ogrons rather unconvincingly. In fact the production team may have possibly been limited to '''two''' Daleks by Creator/JonPertwee's estimate (again, the series nearly wrote off the Daleks and didn't have that many props on hand), nowhere near enough to depict a fearsome battle.
* ExcuseMeWhileIMultitask: The Doctor is suddenly attacked by a terrorist. The Doctor throws him to the ground, finishes his glass of wine, ''strolls'' over to the table to put it down and straightens up in time to intercept the man's next attack.
* FacingTheBulletsOneLiner: The Controller, just before he gets, well, exterminated:
-->"Who knows? I may have helped to exterminate you,"
* FailedASpotCheck: An EpicFail. Early on, the guerrillas capture the Doctor and Jo at Styles' estate and successfully hide them from UNIT...by hiding them in the cellar. Not a secret passage, just a cellar with a normal cellar door that's in plain sight. Yates and Benton even enter the same room that has the cellar door while looking for the Doctor and Jo and [[IdiotBall it never occurs to them to check the cellar.]]
* FoodPills: The Controller claims that food in his time is almost invariably in pill form.
* GeorgeLucasAlteredVersion: The serial was given a DVD release containing CGI effects, newly shot footage and new Dalek voices performed by Creator/NicholasBriggs, who has provided the voices for the series since the 2005 relaunch.
* HeroicSacrifice: Shura.
* HollywoodDarkness: "We'll wait 'til it's light", says the time traveller who's just materialised in broad daylight. ''Presumably'' they were trying to shoot day-for-night, but it... doesn't really work.
* {{Jerkass}}: Captain Yates suddenly turns into one for this story, in particular during the first episode, when Jo fetches Benton some food and drink, only for Yates to chase Benton away and take it for himself. When Jo calls him out on it, Yates flat-out admits abusing his rank for the sake of feeding his face.
* KillerSpaceMonkey: The Ogrons, dim-witted mooks of the Daleks, put on their first appearance.
* LaResistance: Played straight by the time-travelling guerrillas, albeit with the twist that they inadvertently caused the Dalek occupation in the first place.
* NewscasterCameo: Reporter Alex MacIntosh appears as himself reporting on the peace conference.
* OhCrap:
** The Daleks get one when they discover that Jo isn't on her own.
--->'''Controller:''' The girl referred to a companion in her own time zone. She called him... "the Doctor".\\
'''Dalek:''' Doc-tor? Did you say "Doc-tor"?!
** Also the Guerrillas when they realise that [[StableTimeLoop they caused the explosion they were trying to prevent]]. Doubles as MyGodWhatHaveIDone.
* OutOfCharacterAlert / QuietCryForHelp: The Doctor finds a subtle way to secretly call for help when he is held prisoner and forced to phone the Brigadier:
-->''"I assure you, Brigadier, there's nothing to worry about. Tell Styles that. Tell the Prime Minister. And, Brigadier, be particularly sure to tell it to the Marines."''
* PantyShot: Well what do you think happens when Jo climbs down a long ladder whilst wearing a miniskirt?
* PeaceConference
* PillarOfLight: In the DVD special edition, the Daleks' Time Vortex Magnetron creates one.
* TheQuisling: The Controller, though he also fulfills the RedemptionEqualsDeath trope.
'''Controller:''' Who knows, I may have helped to exterminate ''you''.
* RedemptionEqualsDeath: The Controller.
* SanDimasTime: The Doctor attributes the "eight minutes in the past = eight minutes in the present" thing to the "Blinovitch Limitation Effect". Mind you, that's his excuse for everything time-related.
* ScrewDestiny: The rebels go back to the 20th century to blow up a politician they blame for assassinating a roomful of international dignitaries and starting World War III, leaving the Earth weak and open to a Dalek invasion. [[YouAlreadyChangedThePast It's eventually revealed that it was]] ''[[YouAlreadyChangedThePast their]]'' [[YouAlreadyChangedThePast bomb that caused the explosion.]] However, UNIT intervene and safely evacuate them all, averting disaster and leaving the future more open.
* SenselessSacrifice: Shura, in the original timeline where he blew up the house, killing Styles and all the delegates, which led to the very war he was trying to prevent. Averted in the new timeline, where it becomes a HeroicSacrifice by blowing up the house and destroying the attacking Daleks and Ogrons.
* SetRightWhatOnceWentWrong
* SommelierSpeak: The Doctor describes Styles' wine as "a touch sardonic perhaps, but not cynical".
* StableTimeLoop: Humans from the future attempt to blow up UNIT headquarters to prevent someone from bombing a ministerial-level conference to be held there, starting WorldWarIII and allowing the Daleks to invade. As it turns out, it is their bomb that they are trying to prevent.
* TimeyWimeyBall: One of the earliest in ''Doctor Who''. Had already been touched on in "The Space Museum" but this could be seen as the TropeCodifier for Doctor Who.
* VichyEarth: the Daleks have installed an apparently efficient system of willing human 'quislings'. It seems the Daleks have learned to keep people in order via more subtle methods than just sticking a radio receiver in their brains. Their collaborators are provided with sharp tailoring, cushy lodgings, blonde female staff and plenty of fruit and nuts. To do their really dirty work, they're employing the Ogrons, a race of interstellar mercenaries. The Daleks themselves remain largely hidden behind the scenes.
* TheXOfY