When the Sunnydale High gang arrives on college campus, Willow and Oz -who even knows the site and people from his band, which has a cool house- take to academic life like a duck to water, Buffy like a fish on land, miserable with a plain roommate she can't confide in, lost, making a fool of herself with one of the rough, demanding professors. Buffy literally bumps into charming teaching assistant Riley Finn, but he is clearly more interested in fellow psychology buff Willow. Another literally lost student, Eddie, seems nice, but disappears the next morning. Buffy smells vampires, indeed a whole nest has formed a sorority. Visiting Giles, she finds him with a scantily dressed visitor, Olivia, and is told to mind herself except in emergencies, not the case yet apparently, however he will reconsider later. The vampire president is arrogant, hopefully enough to underestimate Buffy, who is greatly relieved to find Xander is back from his summer touring...

From the start Buffy didn't get along with her fussy, girlish roommate Kathy Newman, who seems to have a different taste in all matters, but Kathy seems determined to follow her around. One evening Buffy shoves her out of the way to fight off one demon of a lurking type which Giles, to whom she turns in search of anything familiar, later determines as trans-dimensional. Even Parker Abrams, the nice, helpful older student Buffy met, who came for her to their dorm room while she patrolled, seems more interested in Kathy. The antagonism between the rivaling roomies grows to a 'demonic' dimension, while Buffy believes that Kathy's fingernails growing back daily must be a monster-characteristic. At last the gang decides to intervene, but an unexpected other interested party...

Willow is bitten by bimbo friend Harmony Kendall, who turned vampire at the end of season 3, Oz chases her and she threatens her boy-friend will beat them up- that's actually Spike, who has a secret new underground layer and troop to dig for a crypt. Now Kathie is out of the way, Parker Abrams, who switched major from medicine to history, is ready to kiss Buffy, but the vampire alert (a 'bad puppy' is all they tell him) gets priority for a while. Harmony makes Spike bump into Buffy, he says it's too early, she blurts out they're after the stone of Amara, according to Giles a fictitious vampire grail-equivalent rendering invulnerable. Anya is eager enough for sex with Xander to strip for him- his objections last a mere minute. Buffy gets into Parker's bed, but no commitment either. The whole gang is summoned by Giles, who found the gem may indeed be in a crypt in the 'Valley of the Sun' i.e. Sunnydale; Spike already found it and dumped childish Harmony...

In the Halloween night, Buffy is very depressed due to her non-corresponded feelings for Parker, and Willow, Oz and Xander convince her to go to a famous Halloween party in a fraternity with them to have some fun. Anya is also invited by Xander to join the group. However, while decorating the place previously, one of the hosts paints a magic symbol, the Mark of Gachnar, on the floor, and an accidentally spilled drop of Oz's blood awakens the Fear Demon Gachnar who is fed by fear, bringing panic and horror to life on the house.

Gloomily gazing at Parker, who has moved to another one-night-conquest, still enamored Buffy misses out on another chance to approach charming teaching assistant Riley Finn in the college bar and accepts an invitation from some arrogant students. Those grossly embarrass the new barman, Xander, who finds the work and his boss harder then expected, while feeding Buffy gallons of pedantic crap and their adored 'panacea' beer Black Frost, which contains an inhibitions-blocking, addictive concoction, taken in such large quantities even turning them into ape-men, losing speech, wielding cudgels, setting fire to the college bar. Grumpy because her Oz has eyes for another band's female singer, Willow spits at 'never evolved, sex-obsessed' men to Parker, the cavemen knock them down. Giles loses her track after realizing Buffy's regression, but brave Xander kept up and saves the students from the fire; only her ex Parker is left to Buffy, who already felt like hitting him vindictively...

Just as Buffy discovers increased werewolf activity on campus, Oz escapes from his cage during a full moon and runs across another werewolf, the sultry, sexy singer Veruca, and wakes up next to her naked in the wilderness the next morning.

Spike is captured by the paramilitary commando in the campus, but escapes from a hi-tech facility unable to bite or fight against humans. Meanwhile, Riley Finn (Marc Blucas) finds that he likes Buffy, but is incapable of establishing a dialog with her.

It's Thanksgiving, and Buffy pushes Giles to host the gang 'as a real American'. Ankya finds her lover Xander particularly sexy in his new construction laborer's job, digging a deep hole during the ceremony for the newly built Cultural Center at UC Sunnydale, but he falls badly into an Indian grave inside the ancient mission, and thus releases the revengeful spirit of the Chumash warrior Hus, who can transform himself into green smoke or various animals, and starts by killing the curator with an 19 century ceremonial Chumash stone knife. The fact that Xander gets the very diseases (sick he seems as erotic to Ankya as sweating bare-chested) the Chumash contracted while virtually enslaved in the colonial era, and the choice of Hus's victims make Willow, who feels very guilty for the plight of the natives, and Giles, who insists Hus's victims are innocent, realize he must be after historical vengeance. Meanwhile Riley Finn's military Initiative commandos team continues implants rendering vampires unable to bite victims, notably Sîke, who is now chased from the hell-mouth by petty Harmony, and seeks refuge at Giles's, where he is however tied up. Angel is also around again, but insists to Giles and Willow -who disagrees- not to tell Buffy. Hus returns to the grave site to awake more Indian spirits, which jointly mount an attack on Giles's home during the dinner, wielding traditional weapons...

Willow has another try at active magic, trying to cure her lovesick longing for Oz by means of a spell which makes her will come true, but thinks it failed while it's only delayed and sometimes works otherwise, more literally then she meant, so without anyone realizing for a while she blinds Giles, switches Amy from rat to girl and back, teleports Buffy, makes her tell off Riley because she and Spike fall madly in love and actually plan a wedding and makes Xander attract demons. Only when Anya, Xander and Giles, who was looking for magic to help Spike with his feeding problem, figure out what has happened can the magic be reversed, but the council of the upper demon D'Hoffryn, who granted her spell, has summoned Willow, intending to recruit her as a powerful evil witch, not the failure she believed to be...

The creepy demons "The Gentlemen" capture the voice of the population of Sunnydale, to steal human hearts without scream. Giles find that in accordance with a legend, the creatures will be destroyed if a lady screams, but Buffy's gang plus Riley must fight the monsters voiceless.

While Buffy and Riley disclose their secret lives to each other, three demons try to collect some objects for a ritual of sacrifice to open the Hellmouth for the Apocalypse. finding that he can fight evil, Spike joins Willow and Xander in their hunt for demons.

Ethan Rayne invites Giles for a couple of drinks and puts a spell on him, transforming Giles in a primitive strong monster. Spike is the only one to understand the language spoken by the monster, and Buffy almost kills him.

When Riley tells the Initiative about Buffy, they invite her to join their ranks. But it soon becomes apparent that her independent attitude and need to question orders may not be what the Initiative is looking for.

Professor Maggie Walsh's only fellow researcher on project 3-14, Dr. Angelman, finds her killed by it, the 'demonoid' she assembled from various monster -, man and machine parts as an ultimate warrior: Adam is now loose and kills without any conscience. Giles can't maintain the Initiative won't come to his home when Riley turns up instantly, so the gang hides at Xander's while Spike barely escapes them by hiding under a corps in a tomb in his crypt, later to become attacked by demons who realize he turned good. Willow and Tara fail to locate the demon by summoning the dark goddess Tespia. Riley gets sick and aggressive -withdrawal from the drugs Maggie secretly mixed in the commandos' food- but goes after Buffy and Xander, who interrogated Willy the Snitch with him earlier and now break into the Initiative's military facility, where Adam also got in and explains he sees Riley as Maggie's other favorite (brain)child; Riley's rejection causes a fight...

Waking up from a long, deep coma having nightmares with Buffy, Faith goes to Sunnydale bent on revenge. Riley leaves the facility and meets Buffy. Looking for Adam, Buffy, Xander and Willow find a demon he dissected in the woods. Faith captures Joyce, Buffy fights for her mother.

Faith and Buffy switch bodies. Trapped in Faith's body, Buffy is kept in police custody, but on the way to the precinct, the Watchers Council's retrieval team provokes an accident with an armored truck and captures her from the police car. Faith enjoys free life in Buffy's body, flirting with many guys in the Bronze, ultimately Ryan, and buys a ticket overseas. Willow introduces Buffy to Tara, who feels an evil aura in her soul. Willow and Tara risk a dangerous astral projection to the Nether Realm beyond the physical world to find the truth. Adam trains three vampires against fear, and they kidnap and threaten everyone in a church. Faith listens to the news in the airport and goes to the church, where Buffy, Riley and the gang are facing the monsters.

When the fantastic Jonathan visits Sunnydale U.C., everybody wants to be with him: the inventor of Internet; lead actor of "The Matrix"; awesome vampire hunter; stunning singer; great author of successful best-sellers; amazing lover. Meanwhile, a weird and powerful long-armed demon also comes to Sunnydale, marked with an unusual signal. When Buffy sees the same signal on Jonathan's shoulder, she feels that something is not right in the reality.

It's becoming clear Adam is bridging the natural 'racist' aversion between demons and vampires. Spike eagerly stirs Anya's insecurity, even fearing a second sex-less night means Xander, who now runs an ice cream cart, is either no longer in love or physically flaw. Riley performs great in bed upstairs with Buffy and has planned a party downstairs in the frat house, mainly for the other commandos' moral. There weird, even scary things start happening, which drive everyone out. Willow and Giles discover that Lowell house formerly was a home for problem teenagers, where the prudish, still living director Genevive Holt, punished 'dirty deeds' so horribly that several victims have become poltergeists, who now draw energy from the love-making upstairs...

In the full moon, Oz returns to Sunnydale and spends the night with Willow telling that he was healed of the wolf thing in Tibet, using meditation, drinking some teas and using some charms. Willow has no courage to tell him her relationship with Tara. When Oz finds that Tara and Willow are in love, he becomes upset, loses control and transforms in a werewolf, being captured by the Initiative. Riley tries to help him, but is arrested. Meanwhile, Spike closes an agreement with Adam, and guides the Scooby group to the Initiative to release Oz and Riley.

Spike was chosen by Adam to sow discord among the Scoobies, in exchange for eliminating his chip. He succeeds in stirring Buffy's loneliness, Willow's lesbianism, Xander's ineptitude and Giles's midlife crisis.

When Buffy sees Spike in Adam's cave, she realizes that Spike is intriguing the Scooby gang to destroy their friendship following Adam's instructions. She meets Willow, Xander and Giles and they apologize to each other. They also realize that the monsters were not captured by the Initiative, but actually they are the Trojan Horse of Adam to fight against the commando from inside. Once Buffy alone is not able to defeat Adam, the Scooby gang decides to transfer the best of each one of them, i.e., the witch power of Willow, the strength of Xander and the expertise of Giles, to Buffy through witchcraft to make her powerful and capable of fighting against Adam. Meanwhile, Riley finds that he has a chip over his heart and connected to his central nervous system to modify his behavior and obey Adam.

Buffy, Willow, Xander and Giles decide to spend the night watching videos at Joyce's home. They fall asleep and they all share a nightmare with the first slayer.