1943, Montgomery, Alabama: Rosa Parks tries to board a bus, but after paying the fare sees there are people standing in the back staircase, where the "coloured" passengers are supposed to enter. She tries to walk down the front aisle, but the bus driver demands she exit and re-enter in the back. When she eventually relents, the bus drives off without her before she can get back on.
1955: The TARDIS lands in an alleyway, and the Doctor notes that this is not Sheffield. Her companions are less than impressed, as this is either the ninth or fourteenth time they've missed their destination. Before they can leave again, the TARDIS' screens inform the Doctor that there's artron energy in the vicinity, which piques her interest since there shouldn't be any. The companions are a bit iffy, but venture forth with The Doctor to see what's up.
While walking down a street, Ryan gets a first-hand introduction to the racism of '50s American South when he tries to return a dropped glove to a white woman, and gets slapped hard by her husband. The others leap to his defence, but before a scuffle can ensue, a woman steps in to defuse the situation: Rosa Parks. After she promises the man that his suit, which she's working on, will be done by tomorrow, the couple storms off. Rosa tells the four time travellers that they should be careful not to cause any trouble, and when she introduces herself, all four are thrilled to meet her, and the Doctor nearly squees. The Doctor manages to prevent any future spoilers from being leaked, but scans Rosa as she walks off, discovering traces of artron energy around her.
The Doctor realizes they have to stay in the past longer, as she deduces that someone is likely trying to mess with history. Meanwhile, in the alley where the TARDIS is parked, a white man in a leather jacket approaches it and scans it with a gadget that definitely isn't from this time period. He then tries to shoot it with an energy weapon, but fails due to its protective forcefield he'll have to do better than that to get in! After the Doctor and her friends, in a bar, discuss Rosa's life, they get kicked out because Ryan is black and Yaz is "Mexican". The Doctor explains that they have a duty to make sure history takes the right course.
Tracking the artron energy leads the Doctor and her friends to Montgomery's bus depot, where they find a suitcase in a locked warehouse, hidden by a Perception Filter, with a selection of futuristic gadgets inside. They are quickly accosted by the owner, the man in the leather jacket. After a chase, the Doctor has a chat with the man, whose name is Krasko, atop a rusted fuel tank. He asks her if her time machine is a TARDIS, claiming that they're worth a lot of money, and the Doctor scoffs at this, claiming hers isn't. She's taken the spare battery for his temporal displacement weapon, and he threatens her, which she's not impressed by. Krasko claims ignorance of Rosa when the Doctor mentions her name, and the Doctor and her friends walk away. When Yaz asks if they're leaving Montgomery, the Doctor responds, "Not in a million years."
Since they can't go back to the TARDIS as Krasko knows where it is, they get a room at a motel, which is unfortunately "Whites Only", necessitating Ryan and Yaz to be smuggled in through the bathroom window in the back. The Doctor starts getting everyone to list what they know about Rosa and her bus ride, since it's obvious that the time traveller they met is trying to interfere. She starts writing on the wall with a marker, and Graham objects to the vandalism as she isn't Banksy. Or is she? In any case, the pen is special. The discussion is interrupted by a knock on the door, and Ryan and Yaz flee to the bathroom. The Doctor sonics the ink to turn it invisible, and opens the door to reveal a police officer. Apparently, our heroes have made some "good citizens" uncomfortable with their non-bigoted views. Graham claims that they are in town to sell an invention, effectively describing a smartphone (hilariously attempting to use terms appropriate to the 1950s), and then claims his name is Steve Jobs. The officer is skeptical, but when he enters the bathroom, it's empty. Ryan and Yaz have slipped out to the alley and hidden behind a dumpster, where they discuss how uncomfortable it is to be in the racist past, while also talking about the racism they each face in their own time.
After Graham gives Ryan and Yaz the all-clear, the brainstorming resumes, as the Doctor states that they need every bit of information about what happened the night of Rosa's bus ride, especially since a newspaper reveals that it's supposed to happen tomorrow. And the Doctor suspects that the time traveller she met is going to do whatever he can to try and steer history off-course. After a lot of hard work, they deduce where Rosa lives, where she works, and which bus route she's going to take. Graham goes to the bar to track down the bus driver, James Blake, and Ryan goes to Rosa's house, where he serves coffee and meets Martin Luther King, Jr. The Doctor, meanwhile, confronts Krasko and tricks him into sending his suitcase of gear to the far future with his temporal displacement weapon. She further identifies him as a former inmate of the Stormcage Containment Facility with a neural implant preventing him from hurting or killing anyone, due to a history of mass murder. She tells him that his plan isn't going to work, confiscating his weapon and destroying his vortex manipulator (effectively stranding him in 1955), before leaving.
When everyone meets back up at the motel, Graham has news: Krasko's been at it again, arranging for Blake to get a day off so he's not driving the bus Rosa will be riding. From then on, it's hard work, as the Doctor and her friends have to get the substitute bus driver out of the way, and then overcome a sabotaged bus and false signage to get all the right elements in order. The Doctor even rips her coat and takes it to Rosa's place of work as an excuse to have Yaz keep an eye on her in case Krasko tries anything. That evening, as Ryan is attempting to make sure there are enough white passengers on the bus so that Rosa will be asked to move, he runs into Krasko, blocking the street with a car. Krasko reveals his motives are racist, so Ryan uses the temporal displacement weapon, which he swiped from the motel room where the Doctor left it, to send Krasko into the distant past, since he seems to already like living in the past so much.
Ultimately, all four time travellers end up on the bus with Rosa, and the Doctor, Graham and Yaz have to stay on board to ensure there are enough "white" passengers for Rosa to be asked to move, something none of them are comfortable with. Furthermore, when he gets up to leave before the Doctor can tell him this, Graham unwittingly and unwillingly becomes the passenger for whom Rosa was demanded to give up her seat, directly leading to her refusal and arrest. After Rosa is arrested, back on the TARDIS, the Doctor tells her friends that Rosa's life didn't get any easier, but that in 1999 she was eventually awarded a Congressional Gold Medal. As a final note, the Doctor takes them to see the asteroid that was named in Rosa's honour.
- Agitated Item Stomping: The Doctor destroys Krasko's vortex manipulator by ripping it off his wrist and stomping on it, even animatedly jumping on it.
- Ambiguously Brown: In-Universe. The natives don't recognize Yaz's ethnicity and assume she's Mexican, much to her annoyance (she's really Pakistani). This causes running confusion among the modern Brits, since she gets filed as "white" and "coloured" for the purposes of local laws apparently at random—she gets kicked out of a white-only restaurant along with Ryan, but she's allowed to sit in the white section of the bus.
- Arson, Murder, and Jaywalking: The Doctor's concluding Info Dump about what Rosa Parks' protest achieved gives us a non-comedic and probably accidental example: she got the buses desegregated, inspired other civil rights protests, won the Presidential Medal of Freedom, and had an asteroid named after her. The last of these superficially sounds like a great honour, but is actually comparatively mundane.
- Artistic License History:
- The episode mostly does a great job of presenting Rosa Parks' story, but fudges one detail that can probably be chalked up to budget: her 1943 encounter with James Blake occurred during a drenching downpour.
- There are conflicting accounts as to whether or not Rosa Parks planned her protest, or if it was a spontaneous event due to circumstances. The episode follows Rosa Parks' description of events.
- Although the door is left open, since Rosa is apparently having secret meetings in her home with civil rights activists, including the then-unknown Martin Luther King Jr. What they discuss we don't see, but it's completely plausible that they were discussing Rosa's future act.
- The large clock on the wall of Rosa's workplace is an Ikea Bravur clock, a design which didn't exist in 1955.
- Asteroid Thicket: The asteroid named after Rosa Parks is shown in the midst of one.
- Bad Liar: Krasko's attempts at feigning ignorance of who Rosa Parks is, and later why he's here, are decidedly less than convincing, and the Doctor doesn't hesitate to call him out on it.
- Bait-and-Switch: The intro makes it look like the episode's conflict is caused by the bus driver attacking Rosa Parks. In reality, the intro simply takes place twelve years before the actual conflict.
- Been There, Shaped History: Due to Krasko's interference, the Doctor, Graham and Yaz (who, although of Pakistani heritage, was counted as white by the bus driver) have to stay on the bus so there will be enough white passengers aboard for Rosa to be asked to move. Understandably, none of them are comfortable about this, since they have to watch her get arrested. (Ryan was on the bus as well, but, as he's black, was in the back.) Graham was even the one who triggered the incident, after he got up and someone took his seat, prompting the bus driver to ask one of the black passengers to give up their seat.
- Beethoven Was an Alien Spy: The Doctor claims, perhaps in jest, that she is Banksy.
- Bittersweet Ending: History is back on its proper course, but the Doctor and her friends have to watch Rosa get arrested. The Doctor says that Rosa's life wasn't any easier afterwards, either, since she and her husband lost their jobs.
- Butterfly of Doom: Krasko attempts to create enough tiny changes in history so Rosa either won't take the bus or won't have to rebel by refusing to give up her seat. The Doctor and her friends manage to prevent them, keeping history on the right course.
- Krasko is a former inmate of Stormcage Prison, where River Song spent some time.
- The Doctor still derides the Vortex Manipulator as inferior to the TARDIS. She also describes it as "cheap and nasty", the same terms that the Eleventh Doctor used in "The Big Bang", and Missy later echoed in "The Magician's Apprentice".
- Casting Gag: Josh Bowman played Jack the Ripper in the short-lived TV adaptation of Time After Time, another bigoted, time-travelling villain trying to Make Wrong What Once Went Right.
- Changed My Jumper: None of the locals take note of our Main Characters' anachronistic clothing, especially not the trousers the Doctor and Yaz are wearing. This could be justified by the foursome's obvious Britishness; it's unlikely many people in 1955 Alabama knew much about fashion in England at that time.
- No excuses for the Doctor's coat, however, which Rosa spends a few hours mending without noticing anything odd, like unusual fibers.
- Character Title: The episode is named after Rosa Parks, the central figure of the episode.
- Chekhov's Gun:
- When Graham asks if they can go see Elvis, the Doctor mentions that he's in New York, and then reveals that she left a mobile phone with him once. They are later able to get the substitute bus driver out of the way because it turns out that Elvis loaned the phone to Frank Sinatra, enabling the Doctor to get tickets to one of his shows in Las Vegas.
- The Doctor manages to find out the location of Rosa's house by approaching her on the bus and claiming she's doing a questionnaire for a raffle. Later, she and Yaz claim a raffle prize as how they are able to offer the substitute bus driver an all-expenses-paid trip to Vegas.
- When the Doctor brings Krasko's confiscated weapon back to the motel room, Ryan expresses interest in it and asks what it is. It's not very surprising when, during his confrontation with Krasko, Ryan reveals that he's swiped it and uses the weapon to send Krasko off to the distant past.
- Clothing Damage: The Doctor deliberately rips her coat so she can take it to get repaired by Rosa, giving Yaz an excuse to stick around at the department store in case Krasko tries anything.
- Continuity Nod:
- The Doctor tells a historical figure she's their fan, and gets a confused response.
- The Doctor scoffs at Krasko's assertion that TARDISes are worth a lot of money, claiming that hers isn't because it's used.
- Krasko implies he got his vortex manipulator off the black market. It wouldn't be the first time.
- Krasko's gun is similar to a Weeping Angel's touch.
- Counting Bullets: A variation happens with Krasko's temporal displacement gun. The Doctor is able to surmise that he's drained the gun's charge based on the setting and the number of times he's fired it, and with the spare battery currently in her possession, he isn't going to be firing it again.
- Cruel to Be Kind: The Doctor and her companions have to stay on the bus so it will be full enough for the driver to order Rosa to move, and because history needs to play out, they can't help when that happens. Graham is horrified but reluctantly goes along with it.
- Deliberate Values Dissonance: Ryan notices a white woman drop a glove within seconds of stepping around 1955. His reward for his troubles is being slapped in the face by her angry husband, for having the temerity to approach a white woman. The episode brings up a major point that there are many periods and places in Earth's past that would be uncomfortable or even hazardous for a non-white time traveller to visit.
- Didn't Think This Through: Krasko intends to change history by making sure that Rosa Parks doesn't have her famous moment of protest on the bus, and to accomplish this he sabotages events so the buses will either be out of service or there won't be enough passengers to require her to move if the buses are still going. There are some problems with this plan due to either research failure or the subject of the story:
- In Real Life, Rosa, an activist rather than an Accidental Hero, was determined to go through with it. Sabotaging the buses on a single day would delay her, but it certainly wouldn't stop her. Krasko would have to follow her for a very long time to actually stop it. The episode portrays it as more of an incidental situation brought on by a confluence of coincidences. Though, as noted above under Artistic License History, there are conflicting accounts of exactly how planned Rosa's protest was, and the episode chose Rosa Parks' account.
- As famous and inspiring as this event was, it is extremely implausible that preventing Rosa Parks from carrying out her protest would have any major impact on the history and development of civil rights- she was, at the end of the day, just one protest amongst many before and since, and even if Krasko had outright erased her from history the timeline likely wouldn't have been altered all that much as someone else would just have led the charge instead; at best his scheme would have delayed the movement by a few years, more likely mere months or weeks. It was arguably already too late since the US Supreme Court had already ruled segregated busing unconstitutional in a previous case. Which was why Rosa's made such a strong rallying point; the law she broke was morally AND legally indefensible. While his intentions are horrible, his Evil Plan is rather laughably dumb.
- Disappointed by the Motive: After a whole episode in which our heroes believe that Krasko has some grand plan behind his Make Wrong What Once Went Right scheme, the discovery that he really is doing all of this just because he's some random two-bit racist that managed to get his hands on time-travel technology induces enough rage in Ryan to shoot him... with the time-displacer-gun, leading to a Fate Worse than Death.
- Enter Stage Window: The Doctor and company, since they have to avoid the TARDIS as Krasko knows about it, get a room at a motel that's "Whites Only". So Ryan and Yaz have to sneak into the room through the bathroom window, in the back.
- Everybody Lives: Krasko may have been zapped to the past, but he was still alive.
- Evil Cannot Comprehend Good: Krasko's plan is to merely stop Rosa Parks' protest by either delaying the bus or by changing the driver. He fails to comprehend how Rosa Parks is determined to fight for civil rights regardless of the circumstances, even if the actual event is delayed by a day or two.
- Exact Words:
- The Doctor uses these to hide Yaz and Ryan from a racist police officer in a "Whites Only" motel.Officer Mason: You don't happen to know a couple of, ah... mongrels? Hmm? Negro boy? Mexican girl?
The Doctor: I don't recognize anyone by that description.
Officer Mason: See, the negro's been goin' around pickin' fights with... upstanding citizens. You appreciate it's a... it's an offense to harbour coloureds in a room here?
The Doctor: We're not harbouring anyone who doesn't have the right to be here.
- Also, after Graham has pretended to be "Steve Jobs" in town to try and sell an invention that sounds rather like a smartphone, Officer Mason threateningly demands to know whether Graham is trying to disrespect him. Graham responds that "Steve Jobs" would never be disrespectful of a Montgomery police officer. This, of course, does not reveal whether Graham would.
- The Doctor uses these to hide Yaz and Ryan from a racist police officer in a "Whites Only" motel.
- Fake American:
- In-Universe. Krasko sounds British whenever the Doctor confronts him, but adopts a Southern accent when talking to the people of Montgomery.
- In a meta-sense, most of the cast are British actors playing Americans, including Vinette Robinson as Rosa.
- Krasko and the Doctor. Both ran away from their people with time travel, and their pasts both involve a large amount of bloodshed. They also both use non-lethal methods to achieve their goals. However, the Doctor actively chooses to act non-lethally, while Krasko can't kill due to a Restraining Bolt, and also revels in the number of people he's killed while the Doctor is haunted by it.
- Krasko and River count as contrasting inmates of Stormcage prison. River doesn't enjoy killing anymore, but will do it when there's no other option left. For Krasko, it's his first option kill the person his way rather than explain. Krasko is psychopathic so is River, but unlike Krasko, River is much less psychopathic because she has guiding influences. Krasko is everything River would have been without those good influence.
- At one point when reminiscing, Graham reveals that after she learned he was a bus driver his wife Grace had told him about James Blake trying to force Rosa to give up her seat, commenting that Blake's actions gave bus drivers a bad name. During the climax, Graham is horrified to realize that he has unwittingly become the white passenger for whom Blake demanded that Rosa give up her seat.
- When Ryan confronts Krasko, Krasko boasts that he's already won because, even if Ryan does move his car so the bus will be on schedule, the bus will be three white passengers short of the required amount necessary to force Rosa Parks to move. The bus currently has three passengers in the white section that shouldn't be there: the Doctor, Yaz, and Graham.
- For Want of a Nail: The Doctor is concerned that Rosa's protest not occurring in the exact circumstances that history records it as happening could have serious repercussions for the future.The Doctor: We're one day out from a tipping point in Earth history. I don't want anything disrupting that.
- Full-Name Basis: Ryan repeatedly addresses Rosa Parks and Martin Luther King, Jr. by their full names, to the point of becoming an Overly Long Gag.
- Gender Vocabulary Slip: It takes the Doctor a moment to realize that she's the one being addressed when the police officer calls her "Ma'am."
- Greaser Delinquents: Krasko is dressed as one and works with cars as part of his cover for sabotaging the bus. His usual costume is virtually identical to Marlon Brando's as iconic Greaser Johnny in The Wild One.
- Heroic Resolve: A downplayed example, as the person inspiring the Heroic Resolve is not at that point under direct physical threat in front of the characters. After they're kicked out of the restaurant, the Doctor offers to investigate the situation herself while her companions to go back to the TARDIS, citing that it's incredibly dangerous for them especially Ryan and Yaz to be in 1955 Montgomery and that the Doctor will face less threat. Both Ryan and Yaz reply that Rosa Parks has to face these dangers every day of her life and that they're willing to shoulder them as well if it'll help her, especially since it'll only be temporary for them. They're both affected by the overt and unapologetic racism of that time, but they continue.Ryan: If she can live here her whole life, a coupla hours ain't gonna kill me. It ain't gonna kill me, right?
- Historical Domain Character: Key Civil Rights Movement figure Rosa Parks, as well as Martin Luther King, Jr. and James Blake. Rosa also makes reference to Emmett Till when warning Ryan against approaching white women.
- The meeting at Rosa Parks's house is also attended by Fred Gray.
- Historical In-Joke: When Ryan is told by a waitress "We don't serve negros," he responds the same way as Muhammad Ali, saying "I dont eat them."
- Historical Villain Downgrade: A collective one against racism. Rosa's warning about what happened to Emmett Till downplays the horrors of what happened (his corpse pulled from the water is about the least of it). Similarly, Graham and Ryan outing themselves as family wouldn't make for hilarious tweaking of racists, but a lynch mob coming for them both.
- Historical Villain Upgrade: Possibly. In later years, James Blake insisted that he was just a city employee doing his job. Of course, you could always say that he was lying to make himself look good, but the fact remains that there's no solid historical evidence that he was the dyed-in-the-wool racist portrayed by the episode.
- Hoist by His Own Petard: Krasko, a white racist from the future, is zapped into the distant past with his own temporal displacement weapon by Ryan, a black man from the 21st century (which would be the past to Krasko). The Doctor also tricks him into zapping his own equipment with the same gun earlier on.
- If I Wanted You Dead...: When Rosa catches Ryan following her, she asks if he's spying on her for the FBI. Ryan replies that, were he a spy, he wouldn't be so terrible at keeping himself hidden, wouldn't be British and doubts the FBI has black informants on their payroll anyway.
- I'm Mr. [Future Pop Culture Reference]: Graham tells the Montgomery police officer that his name is "Steve Jobs". (Incidentally, Steve Jobs was born in 1955, the same year in which the episode takes place.)
- In the Future, Humans Will Be One Race: Averted; apparently even in the 79th century white supremacy is still an issue, suggesting that human racial distinctions remain present. One would hope, however, that Krasko is just a throwback.
- Invisible Writing: The marker the Doctor uses to brainstorm on the wall of the motel room has special ink that can be sonicked invisible.
- It Will Never Catch On: Graham improvises a cover story for the police officer's benefit about coming to Alabama to pitch an invention, and then describes what's essentially a smartphone. The officer replies that the idea sounds ridiculous.
- The Knights Who Say "Squee!": The Doctor, Graham, Ryan and Yaz are thrilled when they first meet Rosa, to her understandable confusion. Later, Ryan is thrilled when he gets to meet Dr. Martin Luther King, Jr. at Rosa's house.
- Last-Second Word Swap: After telling Rosa that she's a fan of hers, the Doctor then quickly states that she's a fan of... Montgomery, to avoid letting her know they're time travellers.
- Locked Out of the Loop: Unlike some other historical figures the Doctor and companions have interacted with, Rosa never learns about the Doctor or time travel.
- Ma'am Shock: The Doctor is once again caught off-guard by being called ma'am due to not being completely used to her new gender yet.Police Officer: Can I come in, ma'am?
The Doctor: [muttering] "Ma'am." Still can't get used to that.
- Make Wrong What Once Went Right: Krasko is opting to prevent Rosa Parks from being ordered to give up her seat, which would have potentially catastrophic effects on the timeline because it would undermine the generations-long fight for equality between races. And with two of her current companions being non-white, the Doctor has a personal stake in making sure their futures aren't affected.
- Meaningful Background Event: While the Doctor and her friends are investigating the suitcase inside the bus service depot, Krasko can be seen slipping into the building behind them.
- Meta Twist: The motive behind Krasko's actions remains vague, implying that Rosa's stand on the bus has even further reaches into the future than just desegregation, until Ryan confronts him alone, and it turns out that Krasko is just bigoted like James Blake.
- Mistaken Nationality: Yaz is mistaken for Mexican, since the locals aren't very familiar with South Asians. This becomes a Running Gag between her and Ryan. Oddly enough, if Yaz had been truthful about being a South Asian, she might have had less harassment.
- Mood Whiplash: Graham recalls how he learned about James Blake from Grace when they first met, and wishes she were here. After a sombre moment, Ryan says he's glad she isn't, because she'd probably start a riot. Everyone gets a good laugh out of this.
- Mundanger: Turns out that racism as we know it (and Rosa Parks had to endure) is something that will always exist, even several hundred years in the future. This actually disgusts Ryan enough to shoot Krasko (with a temporal displacement gun, but still) and makes moving around town more difficult for most of the companions.
- Newspaper Dating: The Doctor already knows the year thanks to the TARDIS, but does this to deduce that it's the day before Rosa's famous bus ride.
- No Equal-Opportunity Time Travel:
- Ryan is rather worried about this trope applying to him but he and the others can't get out of Montgomery immediately because if the timeline is changed by the antagonist, his and Yaz's present could end up very, very different if it exists at all.
- Graham also gets some very dirty looks whenever he calls Ryan his grandson. Notably, Ryan never argues with him about it this time.
- Non-Lethal Warfare: Due to his Restraining Bolt implant preventing him from killing, Krasko is forced to alter history in minor ways so Rosa Parks won't get on the bus or doesn't have to rebel. His primary weapon is a device that can send people to forward or backward in time.
- Noodle Incident:
- At the beginning, it's mentioned that Montgomery is either the TARDIS' ninth or fourteenth stop since the Doctor has been trying to get her companions home. In combination with Graham's complaining about how they never stop to eat after getting kicked out of a restaurant later, there's a suggestion that the Doctor and company had a few offscreen adventures between "The Ghost Monument" and this episode.
- The Doctor once lent a cell phone to Elvis Presley.
- Krasko was sent to prison for a crime that killed 2,000 people.
- No-Sell: The TARDIS simply throws up Some Kind of Force Field to prevent herself from being affected by Krasko's temporal displacement weapon.
- Not Helping Your Case: The Doctor mentions at the start that this is her ninth attempt to get her friends back to the present. Graham points out it's actually the 14th.
- Perception Filter: Krasko uses one to hide his briefcase of stuff at the bus depot.
- Playing Gertrude: Rosa Parks was 42 at the time the events depicted in the episode takes place, being played by the 33-year-old Vinette Robinson. Subverted in the prologue, however, which is set twelve years earlier when both actor and character would be closer in age.
- Plot-Irrelevant Villain: Krasko is the villain of the episode and is among the many racists in the episode. Krasko's plan also wouldn't have had much of an impact on history, as Rosa Parks was one of many heroes in the movement.
- Politically Incorrect Villain: Krasko is an unrepentant racist whose entire scheme is to prevent Rosa Parks from refusing to give up her seat on the bus thereby triggering the Montgomery bus boycott and kick starting the civil rights movement. He believes that this will ensure the "inferior races" are in their "proper place" in his future.
- Pre-Mortem One-Liner: Ryan, before he sends Krasko into the distant past, says that if he likes the past so much he should just live there.
- Pretty Fly for a White Guy: After successfully convincing James Blake to go back to his bus route, Graham tries to fist bump Ryan, who refuses.
- Restraining Bolt: Krasko was fitted with a neural implant while in Stormcage Prison that prevents him from killing anyone, due to his history of mass murder. When he tries to choke the Doctor, he lasts about five seconds before he collapses in pain.
- Seamless Spontaneous Lie: When talking to a policeman, Graham calls the Doctor "darling", in order to justify their presence in the motel room. They have to flee anyway, but it's the thought that counts.
- Set Right What Once Went Wrong: The Doctor and her companions practically have to bend over backwards to make sure that history remains on track and Rosa Parks doesn't give up her seat. This involves making sure the bus driver isn't replaced, the bus route isn't cancelled or impeded, and that the bus itself is packed... which sadly means that they have to stay on the bus.
- Skewed Priorities: After the TARDIS crew resolve to find out what's going on with the temporal tampering around Rosa and stop it, Graham anxiously asks if they can still find another restaurant which isn't going to kick them out to have some lunch in first. When the Doctor retorts that there's no time, Graham begins to kvetch about how often that happens.Ryan: We just got thrown out of a bar and that's what you're worried about?
Graham: Not just that!
Yaz: Not sure your stomach's compatible with time travel, Graham.
- Smug Snake: Krasko spends most of his interactions with our heroes with a rather superior smirk on his face. He's also not quite as clever as he thinks he is, and ultimately comes off as a bit of a thug who just so happens to have access to time travel technology.
- Some Kind of Force Field: Krasko deduces the TARDIS has a forcefield protecting it after shooting it with his displacement weapon to no effect.
- Special Edition Title: The closing credits, instead of the usual music, are set to Andra Day's "Rise Up".
- Stable Time Loop: Downplayed, but the episode is this from Krasko's point of view, as his failure to change history leads to him going back in time and failing to change history.
- Stupid Evil: Krasko's plan is crippled by the fact that he can't kill Rosa Parks, forcing him to try stopping the civil rights movement by non-violent and non-lethal means. Krasko himself seems uneducated about the history of the Civil Rights Movement, as he believed Rosa Parks was the only one who could have got the civil rights movement in motion. The episode itself is set in December of 1955; 3 months after the lynching of Emmett Till, whose murder and unjust trial was the inspiration Civil Rights Movement. In December of 1955, Rosa Parks' protest inspired the bus boycott, the first large-scale U.S. demonstration against segregation. Krasko's plan had holes in it due to his own stupidity and ignorance of African-American History.
- Rosa Parks was determined to follow through with her protest; it wasn't circumstantial like Krasko believed. Her secret meeting with the other members of The National Association for the Advancement of Colored People implies that her violation of segregation laws was premeditated.
- While Blake was the driver on the day of Rosa's protest, the episode doesn't portray him as more racist than the average white American of his time period. By that logic, it could have been any white bus driver during Rosa Park's protest. For example, Graham accidentally became the passenger who triggered Rosa Park's protest.
- Blocking the bus route wouldn't have changed much either since the bus could have driven around him, taken a different route, or the bus could have been delayed to have Krasko arrested for obstruction. It's not unusual for a bus to be late to one of its stops and the bus still has to follow its intended schedule. At best, Rosa Parks' protest would have only been delayed until she got another bus since segregation was a common occurrance on the bus.
- Tattooed Crook: Krasko has a tattoo on his wrist identifying him as a former inmate of Stormcage Prison.
- Tranquil Fury:
- Downplayed during the Doctor's initial confrontation with Krasko. She spends most of the conversation barely treating him as a threat, and mainly addressing him with playful disregard. But the moment Krasko threatens to kill her and her friends if he sees them again, all the playful goofiness leaves her face and she tells him with steely eyes and in an quiet but icy tone, "Don't threaten me," before walking away.
- The TARDIS is... less than pleased... putting up a forcefield and then growling at Krasko when he tries to displace her.
- Trapped in the Past: Krasko first gets his vortex manipulator destroyed by the Doctor, and then Ryan sends him into the distant past with his own temporal displacement weapon.
- Troll: The TARDIS has apparently returned to fine form, as this is apparently the fourteenth time that she's failed to get the quartet back to Sheffield in 2018. The Doctor even accuses her of doing it on purpose.
- Underestimating Badassery:
- Krasko clearly doesn't take the Doctor or her friends including the TARDIS seriously, even trying to threaten them and thinking he can intimidate them. This comes back to bite him when the Doctor absolutely refuses to be intimidated, even goading him to attack her by destroying his Vortex Manipulator, trapping him in the 50s and forcing him to reveal his Restraining Bolt, a Weaksauce Weakness as he's unable to directly stop them from guarding the course of history and which gives Ryan the opening to just zap him with his own temporal displacement weapon.
- Krasko tries to shoot the TARDIS with a device to send her somewhere else in time. Fortunately, the TARDIS has a forcefield and, more importantly, is as stubborn as the Doctor probably more stubborn if we're truly being honest and won't go anywhere she doesn't want to, as the Doctor has discovered over the last several million years she just gives a groan in reply to being shot by Krasko, as if saying "really?" with a raised eyebrow.
- The Doctor plays into Krasko's underestimation of them by claiming that the TARDIS is old, has an enormous mileage and one very careless owner; all these things are, technically, true, but the Doctor means them affectionately. The TARDIS works perfectly despite her age and is just a massive troll!
- Krasko doesn't even realize the Doctor is a Time Lord. He clearly thinks she is just someone who just found a TARDIS or stole one. The Doctor doesn't do anything to discourage this line of thought.
- Understatement: The Doctor says she "did not warm" to the police officer that searched the motel room, after she'd spent half the conversation looking like she wanted to punch him for his constant racist comments about Yaz and Ryan.
- Vehicular Sabotage:
- One of Krasko's attempts to derail history involves slashing the tires and smashing the windshield of the bus James Blake was originally slated to drive. So the Doctor and Graham steal a functional vehicle.
- He tries to shoot the TARDIS and send her forward in time the TARDIS, being the brilliant intergalactic time machine she is, is having none of it and just groans as if saying "really?" with a raised eyebrow.
- White Man's Burden: Rosa Parks' impact was allowed to happen through the actions of a white lady, because the white lady prevented a white man from interfering to stop said impact from happening. So the two cancel each other out.
- Who Are You?: Krasko asks the Doctor who she is every time he meets her, but she never answers his question.
- Why Don't You Just Shoot Him?: Discussed when it's pointed out Krasko's had more than enough time to just zap Rosa Parks and be done with it, but instead has been following her around. This turns out to be a clue: Krasko has a neural implant that means he can't kill Rosa, or anyone else for that matter.
- You Cannot Kill An Idea:
- Krasko tries to. He's a released criminal from the future who is unable to kill due to a chip in his head, so he plans to work around it by rearranging history to prevent Rosa Parks from getting on the bus or having to rebel against giving up her seat. His ultimate plan was to prevent racial equality between biracial communities.
- Sadly, this also applies to Krasko's own ideals. White Supremacy is still around even in the 79th Century, and one only need to take a passing glance at the time this episode was made to know it's deeply embedded in Western Civilization on a systemic level.