Fred screams in delight to Gunn when she learns that her paper "Super Symmetry and P-dimensional Subspace" has been published in the journal Modern Physics Review with an invitation to speak at the 31st Annual California Physics Institute Symposium by her old college Professor Seidel, and they begin celebrating by making love. Meanwhile, Angel gets nowhere trying to convince Lorne to tell him what his visions about Cordelia were about when he discovers that Connor has been sneaking into the hotel getting Cordelia's personal items and clothes. Cordelia has been decorating Connor's loft with her things and pasting pictures of herself with other people on the wall, trying to remember what is missing in her life. Lilah pays a wary Wesley a surprise visit at his apartment, giving him an antique knight's helmet as a gift and telling him that she has taken the afternoon off, but Wesley tells her that he has to leave. She sees that Wesley has been reading Fred's published article, which sparks her interest.
Fred's talk about her paper at the seminar, which is attended by Angel and Gunn as well as Wesley and Lilah, takes a sudden turn when a dimensional portal opens above her during her speech and snake-like creatures emerge to kill her just as Lilah leaves the conference room. Angel and Gunn run to the stage and save her. Angel confronts Lilah but she denies having anything to do with the attack. Angel soon realizes she was only there because Wesley was, but warns her that he intends to have a conversation about the firm's recent attack (and brain-suck) on Lorne. Angel reconstructs the events in the lobby of the hotel and remembers a man sitting behind them in the auditorium who was taking pictures during the attack on Fred. Angel and Gunn confront the man in a comic book store, who they discover is a fan of Angel in chat rooms on the Internet and wants to be their intern. He tells them that at least three other physics students have disappeared prior to Fred's abduction into the Pylea dimension six years earlier.
While paying Professor Seidel a visit in his laboratory, Fred discovers that Professor Seidel is the one responsible for the attack on her and the one who transported Fred into the Pylea dimension along with some other classmates of hers whom Seidel feared may outshine him someday. Against Angel and Gunn's advice, Fred goes to Wesley's apartment and asks for his help for some mean-spirited revenge against her former mentor. While searching his books for an appropriate punishment, a portal opens in Wesley's living room that almost sucks Fred in. Meanwhile, Cordelia is being taught by Connor how to slay vampires and demons while a possible romance between them blossoms.
Wesley drops off Fred at Professor Seidel's laboratory. Angel, who has arrived there first, confronts Seidel but is attacked by a demon that Seidel conjures up from a book of magic. Seidel attempts to escape but is intercepted by Fred brandishing a cross bow. She opens a portal to a hell dimension, and Seidel desperately holds onto a laboratory counter to avoid being sucked in. Gunn bursts into the room asking her not to do it and that there will be another way. He goes to Seidel and breaks his neck before tossing his body into the portal. When they arrive back at the hotel, Angel notes that both Gunn and Fred are quiet about what happened to Seidel, although he has apparently been told that Siedel simply fell into his own portal rather than knowing the full details about the confrontation. After Gunn and Fred go back to their room, Cordelia arrives and asks Angel if the two of them were in love with each other.
- Are You Sure You Want to Do That?: Despite being the Jack Bauer of the demon underworld Wesley calmly tries this with Fred, not wanting her to become a monster like he sees himself as. Then she reveals that Seidel is a serial killer, after which he is on board.
- Attack of the Monster Appendage: A mass of tentacles that popped out of a portal and picked up Angel and Fred. We never saw if it had a body, but each tentacle had its own pincer mouth on the end.
- Beware the Nice Ones / Girl with Psycho WeaponGunn: What do you mean, die?Fred: I don't know yet. But it's gonna be about pain. (opens weapons cabinet, selects a long-handled weapon with a curved blade at the top) The halberd could work. Acting like I'm all addle-brained talking about other dimensions. (mocking) Pylea? Never heard of it. (angry) Right. How 'bout a flail-whipping? Would that take a nice long time?Angel: Hours, if you do it right. Not that you should do it at all. (takes whip from her) Ever.
- Broken Pedestal: Fred is outraged and disgusted to discover that Seidel, the physics professor she idolized, is the one responsible for banishing her to Pylea as a way of Crippling the Competition.Fred: I idolized him, and he sent me to hell. Me and God knows how many others who didn't make it back. So-so sure! I'll calm down when he's dead!
- Brown Note: Fred answers her mobile to find an incantation displayed on the screen, whereupon a portal opens right inside the room.
- Buffy Speak: This episode is full of demony portal stuff.
- Call-Back: Fred starts writing on the wall again after nearly getting pulled through the portal.
- Cliffhanger: Cordy to Angel. "Were we in love?"
- Comically Missing the Point: Angel finds Gunn flaked out on the couch.Gunn: Girl kept me up all night. She is un-stoppable.Angel: More than I need to know.Fred: (excited) Did Charles tell you? (about her physics article getting published)Angel: He-he didn't describe it...
- Covert Pervert: Connor once again checks out Cordelia's cleavage.
- Crippling the Competition: Professor Seidel's reason for sending Fred and other promising students to other dimensions.
- Distracted by the Sexy: Gunn is determined to read the magazine despite not understanding any of the article on Fred's work, but gives up when Fred starts to smooch and clamber all over him.
- Eating the Eye Candy: Connor appreciates the view when Cordy bends over in a cleavage-revealing top.
- Famed in Story: Angel is quite pleased there are whole forums on him in the "chatty rooms".
- Fanservice: Amy Acker in a Dangerously Short Skirt writhing around on top of J. August Richards. Cordy's Cleavage Window.
- Foreshadowing: Gunn's sensitivity over his lack of smarts. In Season 5 he gets a brain-upgrade in a Deal with the Devil.
- Geeky Turn-On: Fred starts smooching Gunn as he reads her article. Heterotic theories indeed!
- Getting Crap Past the Radar: Fred and Gunn start making out on the bed. Cut to Angel bringing Lorne breakfast in bed.
- If You Kill Him, You Will Be Just Like Him: Ironically Gunn taking matters into his own hands creates a rift with Fred that causes him to lose her anyway.Gunn: Fred, no! If you kill him, I'm gonna lose you.
- Improvised Weapon: Angel beats the demon to death with a telephone — it got better.
- Ineffectual Death Threats: Angel Perp Sweating Lilah isn't as effective as it was."You know, Angel, coming from you, idle threats are so... well, idle."
- Innocent Cohabitation: When Connor comes to pick up Cordy's stuff, Angel hands him her fluffy slippers, saying her feet get cold. Connor says he knows as Cordelia is always pinching the covers. Angel is not happy over what this implies.
- It's Personal: Fred dearly wants revenge for what was done to her and others, to the point even Wesley tries to warn her about seeking vengeance.
- Kill Steal: Gunn kills Seidel so Fred doesn't have to.
- Laser-Guided Karma / Self-Disposing Villain: Angel assumes Seidel opened a portal to a hell dimension and fell in himself. Actually Fred opened the portal and Gunn threw him in.
- Murder Is the Best Solution: The minute Fred finds out that Oliver Seidel, her former physics professor, was the one responsible for banishing her to a hell dimension for five years, she goes full Girl with Psycho Weapon and is out for blood. Gunn argues against Fred killing him, believing that such a brutal act would ultimately destroy her. In the end, Gunn does it himself, snapping Seidel's neck before dropping him into a portal to a hell dimension Fred had opened up as poetic justice. She doesn't takes it well, and it's one of the big steps that makes her ditch him for Wesley.
- Angel: We're gonna get this guy.
Gunn: Count on it. He's gonna pay.
Fred: No. He's gonna die.
- Neck Snap / Mercy Kill: Gunn breaks Seidel's neck before throwing him into the hell dimension.
- Nerd Glasses: Laurie, Seidel's assistant.
- New Powers as the Plot Demands: Angel is able to use his Photographic Memory to mentally reconstruct a crime scene around them and identify a suspect. While in earlier episodes he had demonstrated an impressive memory and other exceptional mental talents (he speaks several languages and can recreate faces almost perfectly), that particular ability had not been shown before.Gunn: How come you never pulled out this parlor trick before?Angel: It's not an automatic reflex. It just kicked in when I saw Lilah.
- No-Sell: "Vampire...strangling...not gonna happen!"
- Not Me This Time: Lilah assures Angel that she had no role in the monster attacking Fred.Lilah: Come on. If I were gonna kill the twig, would I do it in a room full of people and then make a conspicuous getaway so I looked extra suspicious?Angel: Add video tape, sounds like vintage Wolfram and Hart. (Lilah just shrugs) Except this time somebody else deserves the credit.Lilah: You're quick.
- Not Quite Dead / Finger-Twitching Revival: Seidel summons a Voynok demon to fight Angel. Afterwards Angel says the demon had nine lives, though we only see him killing it the first two times.
- Not So Dire: The episode opens on shots of the Hyperion and the sound of a Screaming Woman. Who turns out to be Fred Squeeing over a magazine article featuring her.
- Off with His Head!: Which is good, provided your enemy can't grow a new one.
- Poisonous Friend: When Fred plans to murder (or at least trap inter-dimensionally, which probably a death sentence) her old college professor, who did the same to her and at least four other people, her boyfriend Gunn kills him for her, in an attempt to fulfill this trope. Fred does not take this well at all.
- Punch a Wall: Connor after Cordelia leaves him to see his father.
- Revenge: Fred goes full Girl with Psycho Weapon over Seidel, and after Angel and Gunn speak out against the idea talks Wesley into helping her.
- Remonstrating With An Axe to Grind: Fred venting over what she's going to do to Seidel.
- Self-Deprecation: "This [cue card] just says open with joke, but I forgot to think of one. 'Course, it's possible my theory will take care of that."
- Serial Killer: Fred describes Professor Seidel this.
- Ship Sinking: This episode marks the beginning of the end of Gunn's relationship with Fred.
- Shout-Out: The comic book references — from Gunn Perp Sweating a fan ("Think Daredevil #181. I'm Bullseye, you're Elektra. One wins, one dies. Get what I'm saying?") to Lilah scoffing at Angel's attempt to do the same with "Hulk Smash".
- Shown Their Work: Almost all of the references to string theory, P vs NP and other physical concepts in this episode are real scientific terms and are used in the correct contextcontrary to many other TV shows and movies.
- Smash Cut: Wesley and Fred diving over the couch to escape a portal that suddenly opened, cuts directly to Connor and Cordelia diving into a Suggestive Collision.
- Suggestive Collision followed by the Smooch of Victory: Cordelia/Connor after staking a vampire.
- This is Something I've Got to Do MyselfWes: I'd ask to tag along—Fred: But you know what the answer would be.
- Technobabble: Lots, since theoretical physics features prominently in the episode. Amusingly, one of the scenes has Fred muttering about "P versus NP" and "non-deterministic polynomial time" which is computer science and has nothing to do with physics.
- This Is Gonna Suck: Professor Seidel summons a demon to attack Angel when he confronts him. Angel's response is a weary "Great".
- Twisted Echo Cut:Gunn: Well, get on it, 'cause when my girl's not happy— [cut to him Perp Sweating a witness] I'M NOT HAPPY!
Gunn: We gotta get to him before Fred changes her mind. 'Cause vengeance, it can get ugly.Cut to Wesley: Vengeance. Sounds good.
- And later...
- Unstoppable Rage: Fred finds out that Professor Seidel was the one who sent her to Pylea and that he's sent other girls to varipous dimensions. His reason?, Simply to eliminate the competition. Understandably she does not take it well.
- You Know What They Say:Fred: "You know what they say about payback? Well, I'm the bitch."