Note: Not a Sword was originally released as a separate, nine-chapters long fic
between My Weapon and Elizabeth. When The Seventh Segment was published, Not a Sword is turned into its second chapter as it is where the story fits in the series' timeline. Recap namespace is used for consistency with the other The Seventh Segment substories.
The Doctor, accompanied with Donna, is looking for Excalibur using a device which has directed them to Southern California, to Donna's confusion. The Doctor explains to Donna that Excalibur isn't actually a sword, but a segment to the Key to Time that can look like anything. However, upon exiting the TARDIS, the Doctor is confused because the device leads them to Sunnydale and he is pretty sure that Excalibur isn't there. On the Doctor's order, Donna reluctantly asks the nearest house whether they have seen a sword-that's-not-actually-a-sword, which just confuses the house's inhabitant. Fortunately, the inhabitant is the Doctor's close friend Buffy, who gets teased by her sister Dawn for being obviously not just friends with the Doctor.
The Doctor is surprised by the fact that Buffy suddenly has a sister, since he knows from their previous meetings that Buffy is an only child. However, Buffy seems to think that Dawn has always existed and, thinking that this is simply the first time the Doctor meets Dawn but not the other way around, brings Dawn upstairs to teach her not to reveal a time-traveler's future. Meanwhile, the Doctor reveals to Donna that that he can see that Dawn is actually the Excalibur they are looking for, given a human form and fake memories by a group of monks. As the Doctor sadly remarks that he will have to kill yet another innocent to destroy the Key and prevent a potential multiversal destruction. Donna is horrified and tries to talk him out of it to no avail. When Buffy and Dawn come back downstairs so Dawn can introduce herself, Donna tries to bond with her to convince the Doctor that Dawn is a real person. The Doctor walks outside instead, and Buffy goes after him.
Buffy catches up with the Doctor and asks him to forgive Dawn, thinking this is merely because Dawn has accidentally revealed the Doctor's future. The Doctor tries to tell Buffy that there is nothing wrong, only to find out that Buffy can and has telepathically picked up his emotions when he called her by her real name. He promptly drops the cheerful act and darkly reminds Buffy that he has murdered countless people. Once Buffy realizes that the Doctor is planning to kill someone she loves right now, she knocks him out with a punch, then knocks Donna out too to be safe. As she gets Dawn to help her tie them up in the wooden basement, Buffy explains that she thinks the Doctor is planning to kill her boyfriend Riley, because Riley has been acting weird lately as if he is hiding a superweapon and a future version of the Doctor has told her that Riley is going to try to kill him during their first meeting. Buffy then calls Riley to give a vague warning and then calls Giles so they can do some research on Excalibur.
In Buffy's house, Giles explains to Buffy and Dawn that, based on his research, Excalibur is some sort of key and, based on the Doctor's behavior, is somehow a dangerous one. Meanwhile, the Doctor and Donna wake up in the basement and begin to free themselves. Realizing that the Doctor can't be talked out of killing an innocent child, Donna instead appeal to his friendship with Buffy, pointing out how Buffy would feel if the Doctor kills her sister. The Doctor is taken aback for a bit before continuing to break out of the basement. Upon going upstairs, the Doctor is stopped by Buffy. They become too busy fighting too notice that Donna has sneak Dawn out to the dangerous Sunnydale nighttime with Giles following them. Buffy and the Doctor run outside to find them, with Buffy noticing a trail of "x". However, Buffy only finds the unconscious Giles and Donna at the end of the trail.
Meanwhile, the Doctor has run somewhere else, sensing that Dawn's energy doesn't come from the trail direction. He finds a cave where a Trifaldoreign is capturing Dawn. The Doctor is familiar with the alien's invasion MO: (1) send a scout to set up a warp device to allow the invasion army to come in, and (2) kill a family member of the planet's defender to lure said defender into a trap. The Doctor easily disables the warp device, but his goal now aligns with the Trifaldoreign's: Dawn's death. He can simply sit back without anyone knowing that he could have saved Dawn, but when the Trfaldoreign calls Buffy "little Slayer", the Doctor flashbacks to Elizabeth. How she hates him for not saving her timeline's Sunnydale. Acting on instinct, the Doctor moves to save Dawn and leaves the alien scout trapped in the cave. As Dawn thanks him, the Doctor processes what he has done and realizes that he couldn't bring himself to "destroy" Buffy the same way he did to Elizabeth.
Donna wakes up in Buffy's house to find Dawn telling her sister about the Doctor's rescue. Donna is happy as she realizes that the Doctor has changed his mind. After the Doctor announces that they are leaving now, ignoring the Excalibur issue, Buffy comes to the same realization (except she still thinks the Doctor's target was Riley). As the TARDIS takes off, the Doctor admits to Donna that there is someone he can't bring himself to destroy, and Donna can tell that it's not Dawn.
"Not a Sword" contains examples of:
- Apologetic Attacker: The Doctor apologizes to Buffy as he claims that he is going to do something that will make her hate him forever. Buffy apologizes in return before knocking him out with a punch.
- Bread, Eggs, Milk, Squick: One of the Doctor's internal thoughts describes Donna as "brave, wonderful, brilliant, missing-the-bigger-picture", which would normally be only a downplayed example if not for the fact that "missing-the-bigger-picture" means "wouldn't kill a child for the universe" in this context.
- Call-Back: The Doctor surmises that Dawn is probably unaware of her own status as the Key, because neither was Princess Astra.
- Call-Forward: When describing Excalibur, the Doctor mentions that it might not be a scythe since an actual sycthe is also around Sunnydale, referring to the Scythe from Buffy season 7.
- Continuity Nod:
- In his warning, the Doctor mentions that 2/3 of Earth's population will die because of him, which Buffy remembers is something Omega claims in Don't Be.
- When motivating herself to stop the Doctor from killing people, Donna remembers how she already does such thing in Pompeii.
- When the Doctor tells Buffy, "Then stop me", she is taken aback because she gets reminded of the time in Paradox when she keeps saying that to a future version of him.
- When listing people who knew about the Key to Time, the Doctor also mentions Amy and Zara who debuted in Big Finish's Key 2 Time arc.
- Buffy tells Dawn that the Doctor tells her that Rose turns an entire Dalek fleet to dust once, so they are not taking chance with any of the Doctor's companion.
- The Doctor tells Buffy that he let two-thirds of Earth die and personally killed Susan during the Time War just to prevent the Key from falling into the wrong hands, something previously established in Shoshi's pre-Adventures of a Line Hopper fic Time Walker.
- The Doctor mentions having to deal with Excalibur before, three years ago in Earth time, in adventure involving atomic bombs in England. And he was Merlin. Giles' research even confirms all of it.
- The Doctor introduces himself to the Trifaldoreign as Earth's champion, a title he accepts when he duels a Sycorax in "The Christmas Invasion".
- Damsel in Distress: Dawn gets kidnapped by a Trifaldoreign scout to be killed and used as a bait for Buffy when the main invasion force comes. She is fully expecting Buffy to come and rescue her, but the scout's plan to lead Buffy to a false trail has worked and she gets rescued by the Doctor instead, who has a change of heart about killing or letting her die.
- Dehumanization: The Doctor attempts to justify his plan for Dawn to Donna by saying Dawn is "not a person". Donna disagrees and it is made clear that the person the Doctor is trying to convince is actually himself.
- Entertainingly Wrong: Buffy deduces that the Doctor is planning to kill Riley in order to destroy Excalibur, because the Doctor claims that whatever he is trying to do would make her hate him, Riley has been acting shifty lately, and she knows that Riley is going to try to kill the Doctor when the Doctor first meet him. She is completely wrong because she doesn't count on the possibility that the Doctor may be willing to kill Dawn.
- "Eureka!" Moment: Looking at a wooden chest makes Buffy realizes that the best way to contain the Doctor if she can't find his sonic screwdriver is to put him in the wooden basement where the sonic screwdriver won't work.
- Eyes Never Lie: When the Doctor leaves Buffy's house the first time, he maintains the same chipper attitude, but Buffy notices there is something wrong in his eyes and knows he is concerned about something.
- Have We Met Yet?: When the Doctor shows confusion the first time he meets Dawn, Buffy assumes this is happening as usual because she remembers the Doctor, presumably in his future, meeting Dawn before. In truth, the Doctor knows that Dawn never exists before and Buffy's memories are messed up to make her think Dawn has always been in her life.
- Hesitation Equals Dishonesty: In the final scene, the Doctor takes a long time when Donna asks whether the person he can't bring himself to destroy is Dawn. When the Doctor finally answers "Yes", Donna can tell that he is lying.
- Implied Answer: When Donna asks whether the Doctor is serious about not being able to find Excalibur could mean the end of the universe, he just gives her a glance, which she interprets as a "yes".
- It Gets Easier: Part of why the Doctor is so willing to kill Dawn even if he would hate himself for doing so is because he has killed a lot of people already, some innocents and loved ones included, so killing her for yet another greater good is basically another Tuesday to him.The Doctor: Because I've done it before. Because what's one more innocent life? What's one more death on my head, after I've murdered so many others?
- Layman's Terms: The Doctor explains to Donna that his "toaster" is "psychic augmentation detector" meant to "pinpoint the locus of the psychic interference matrix", among other complicated words. Donna asks, "In English?" to get the Doctor to use simpler words, that they are looking for something that has just popped into existence but they have to deal with a magic spell that causes people to think that something has always been there.
- Morality Chain: Donna attempts to be this to the Doctor by calling him out for his plan to kill Dawn. When her words alone aren't enough to cut it, Donna points out that killing Buffy's sister would mean hurting Buffy's feelings, which temporarily stops the Doctor in his tracks for some moments. In the end, the reason the Doctor stops wanting to kill Dawn is because he cannot bring himself to hurt Buffy the same way he hurt the original-timeline Elizabeth.
- Noodle Incident: When telling Dawn that the Doctor's companions are dangerous as well, Buffy briefly mentions two off-screen adventures with them that she is involved with, one where Martha talks a vampire out of killing her and one where Amy defeat some kind of a slime demon.
- OOC Is Serious Business: Buffy can tell that the Excalibur business is very important and dangerous because the usually-pacifistic Doctor outright tells her that he is planning to kill someone to stop it.
- Percussive Maintenance: Attempted as the Doctor hits his Excalibur-detecting machine repeatedly to try to fix it. It doesn't do anything because, as he realizes later, the machine is right all along as he is exactly where Excalibur (Dawn) is.
- Percussive Prevention: Buffy doesn't fully figure out what the Doctor is planning when he says that someone is going to die, but she knows he is going to do something stupid to his soul and immediately knocks him out to prevent it.
- Preemptive Apology: After telling Buffy that he is going to something that will make her hate him forever, the Doctor apologizes before walking away to do it. Buffy also apologizes just before knocking him out to prevent him from doing it.
- Punctuated! For! Emphasis!: After hearing the story of the Doctor and the Excalibur which involves nuclear bombs, Donna remarks "You. Are. Bonkers" in exasperation.
- Shaped Like Itself: Inverted. Because the Doctor tells her to look for Excalibur while saying that the legendary sword isn't necessarily a sword, Donna ends up asking Buffy whether she has seen "a sword that doesn't look like a sword and doesn't act like a sword".
- She Is Not My Girlfriend: Dawn's first appearance has her referring to the Doctor as Buffy's "secret boyfriend", causing her to reply, "Dawn, he's not my boyfriend!". On the hand, the Doctor is too concerned about Dawn's sudden existence to pay attention to the comment.
- Ship Tease: Donna thinks that Buffy and the Doctor always hug each other in a way that doesn't look like people who are "just mates".
- Shout-Out: Upon finding out that magic is real, Donna jokingly asks if the Doctor is going to bring her to Hogwarts next. She and Dawn then begin discussing the books, although the Doctor reminds her that she shouldn't say anything past the third book (the fourth was only released in 2000).
- Sparing Them the Dirty Work: Buffy is determined to kill whomever the Doctor thinks is so important to kill if it is really necessary, because she feels he has seen too much darkness already and because... just compare their titles ("The Slayer" vs. "The Doctor"). Of course, she never imagines that the Doctor's target is someone in her family.Buffy: If you say that someone has to die to save the universe, I believe you. But you shouldn't be the one to kill them!
The Doctor: I have to. There isn't anyone else.
Buffy: There's me. - Stable Time Loop: Lampshaded by Dawn (although she calls it a "self-fulfilling prophecy"). Buffy has known for a while that Riley is going to try to kill the Doctor in Riley's future and thinks that the Doctor's Excalibur quest is related to it, so she warns Riley that someone is out to kill him. Dawn points out Buffy is just making Riley paranoid enough to be a person who would try to kill the Doctor in the future.
- Tap on the Head: Upon realizing that the Doctor is going to do something messed up, Buffy quickly punches him in the head to knock him up.
- Title Drop: The title gets dropped by the Doctor as he explains Excalibur's true nature to Donna: "It's… actually… not a sword. At all. Just a segment."
- What Measure Is a Non-Human?: At one point, Buffy hopes that Excalibur turns its victims into something nonhuman so she can kill them in the Doctor's place.
- What the Hell, Hero?: Donna spends most of her appearance calling out the Doctor for planning to kill Dawn and trying to talk him out of it.
- What You Are in the Dark: The Doctor gets the opportunity to simply let the Trifaldoreign scout kill Dawn with nobody else knowing that he is nearby and this being an easier way out compared to killing Dawn himself like he originally plans to. He finds himself unable to just stand still as it would hurt Buffy's feelings the same way he destroyed Elizabeth's.
- Would Hurt a Child: The Doctor makes it clear that he would if all of reality is what's at stake and that if he kills early-teen Dawn (whom Donna insists is still a child), it wouldn't be the first time. The Trifaldoreign scout also has no problem killing Dawn for his invasion plan.
- Wrong Assumption: When the Doctor doesn't recognize Dawn, Buffy wrongly assumes that Have We Met Yet? is happening as usual instead of the truth that Buffy and Dawn have Fake Memories.
- "X" Marks the Spot: Exploited. Buffy sees little x's drawn on the ground and assumes they are made by Giles so she can find where he, Donna, and Dawn have gone. They are actually made by the Trifaldoreign who wants Buffy to be led to Giles and Donna's location while he takes his target Dawn somewhere else.
- You Called Me "X"; It Must Be Serious: Buffy already notices something is wrong, but the fact that the Doctor calls her "Buffy" instead of "Elizabeth" as usual cements it (although she doesn't figure out that it is because he is contemplating to kill Dawn).
- You Have GOT to Be Kidding Me!: After being knocked out, tied up, then waking up in Buffy's basement, Donna's reaction is to shout "You have got to be kidding me!"