Trying to find out more about Angel, Buffy and Willow steal one of the Watcher's Diaries to look up on his past. In it, they find a picture of an 18th century noblewoman. Later as they go in search for a costume (at Ethan's costume shop), Buffy finds a red gown like the one the noblewoman was wearing. Willow chooses a ghost costume while Xander decides to be a a soldier. At the warehouse, Spike watches the tape of Buffy fighting and Drusilla tells him that Buffy will be weak on the night of Halloween.
As Buffy and co. takes little groups of kids around the neighbourhood, Ethan is casting a spell in the name of Janus. Suddenly kids in monster costumes turn into monsters, and Willow turns into a ghost. She finds Buffy, who faints as she sees the ghost. Xander and her help Buffy into her house, but Xander and Buffy does not remember what has happened. Willow goes to Giles for help, as Xander saves Cordelia from the little monsters. Strange enough, Cordelia is still Cordelia, rather than a feline. Angel arrives in the midst of the confusion, but he scares Buffy away with his game face.
Buffy runs out into the night, and Angel and co. needs to find her before Spike does. Giles and Willow investigates Ethan's shop when they realise only people who bought their costumes there are affected. But when Giles sees Ethan, he orders Willow to go. A conversation between the two hints at some dark secret in Giles' past but he beats Ethan up and demands to know how to break the spell. In the meantime, Spike has caught up with Buffy, and he reaches to kill Buffy. He pulls at her hair, only to find it's a wig. The real Buffy is back as Giles breaks the statue of Janus.
Buffy soon has the upper hand in her fight with Spike. He leaves. Buffy tells Angel she's dressed up as she did to impress him, but he admits he finds the noble women dull and then they start making out. Back in Ethan's shop, the only trace of the owner Giles can find is a note which says "Be seeing you".
Buffy: Gosh, I'd love to sign up, but I recently developed carpal tunnel syndrome, and can tragically no longer hold a flashlight.
(How Buffy and Willow decide to steal the Watcher Diaries)
Willow: True. It's too bad we can't sneak a look at the Watcher diaries and read up on Angel. I'm sure it's full of fun facts to know and tell.
Buffy: Yeah. It's too bad. That stuff is private.
Willow: Also Giles keeps them in his office. In his personal files.
Buffy: Most importantly, it would be wrong.
(Buffy tries to divert Giles' attention as Willow steals the diaries)
Giles: Buffy! Excellent!
Buffy: Nothing! Hi!
Giles: Yes, I-I just wanted to talk to you about tomorrow night. As it should be, uh, calm, you might work on some new battle techniques.
Buffy: You're beginning to scare me, Giles. You need to have some fun.
Buffy: You know, there's this place you can go, right, and you sit in the dark, and there are these moving pictures, right, and the pictures tell a story.
Giles: Yes, yes, ha, ha, very droll. I'll have you know that I have very, uh, many relaxing hobbies.
Buffy: Such as?
Giles: Well, I enjoy cross-referencing.
Buffy: Do you stuff your own shirts, or do you send them out? (pause) So! How come Halloween is such a big yawner? I mean, do the demons just hate how commercial it's become?
Giles: Um, it's interesting, ac... Not, I suspect, to you. What is it you're after?
Buffy: Of course, it's of interest to me! I'm the Slayer. I need to know these things. You can't keep me in the dark any longer. Look at me when I talk to you!
Giles: I really don't have time for these games.
Buffy: Ms. Calendar said you were a babe.
Giles: She said what?
Buffy: Well, she said that you were a... h-hunk of burning... something or other. So, (exhales) whadaya think of that?
Giles: Uh, I... (exhales) I don't, um, uh... A burning hunk of what?
Buffy: Look. You know how disgusting it is for me to even contemplate you grownups having smoochies, but I think you should go for it.
Giles: Buffy, I appreciate your interest, but...
Buffy: But I've overstepped my bounds. It's none of my business, you know. What was I thinking? My God! Shame, shame. I gotta go. (walks off)
Giles: A babe? (smirks) I can live with that.
Willow: She looks like a noble woman or something. Which means being beautiful is sort of her job.
Buffy: And clearly this girl was a workaholic. I'll never be like this.
Willow: C'mon! She's not that pretty. I mean, look at her. She's got a funny... uh, waist. Look how tiny that is.
Buffy: Thank you. Now I feel better.
Drusilla (to Spike): Do you love my insides? The parts you can't see?
Spike: Eyeballs to entrails, my sweet.
Xander (on first seeing Buffy's costume): Too bulky. I prefer my women in spandex.
Xander (seeing Buffy in her costume): Private Harris reporting for...Buffy! Lady of Buffdom, Duchess of Buffonia, I am in awe! I completely renounce spandex!
Cordelia: Oz. Oz.
Oz: Hey, Cordelia. Jeez, you're like a great big cat.
Cordelia: It's my costume. Are you guys playing tonight?
Oz: Yeah, at the Shelter Club.
Cordelia: Is Mr. I'm-the-lead-singer-I'm-so-great-I-don't-have-to-show- up-for-my-date-or-even-call gonna be there?
Oz: Yeah, y'know, he's just going by 'Devon' now.
Cordelia: Well, you can tell him that I don't care, and that I didn't even mention it. And that I didn't even see you. So that's just fine.
Oz: So, what do I tell him?
Cordelia: Nothing! Jeez! Get with the program.
Oz: Why can't I meet a nice girl like that?
(First time Oz talks to Willow!)
Oz: Oh! I'm sorry.
Willow: Sorry.
Oz: I'm sorry.
Willow: Sorry.
Oz: Sorry.
Buffy: A DEMON! A DEMON! A DEMON!
Willow: That's not a demon. It's a car.
Buffy (looking at a photo of herself): This... this could be me.
Willow: It *is* you. Buffy, can't you remember at all?
Buffy: No! I, I don't understand any of this! Uh, uh, th... This is some other girl! I would never wear this, that low apparel, and I don't like this place, and I don't like you, and I just wanna go home!
Willow: You *are* home! (to Xander) She couldn't've dressed up like Xena?
Xander: She must be right. We must have some kind of amnesia.
Buffy: I don't know what that is, but I'm certain I don't have it. I bathe quite often!
Spike (closing in on Buffy): Look at you. Shaking. Terrified. Alone. Lost little lamb. (pause) I love it.