As Buffy gets to know a charming student named Parker, Spike searches for a ring that, according to legend, makes the wearer invincible.
Willow is bitten by bimbo friend Harmony Kendall, who turned vampire at the end of season 3. Oz chases her and she threatens him with her boy-friend, who will beat them up- that's actually Spike, who has a secret new underground lair and troop to dig for a crypt. Now that 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 and she blurts out they're after the Gem of Amara. According to Giles the gem is a legendary vampire grail-equivalent rendering the holder invulnerable. Anya is eager to have sex with Xander and strips 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 has discovered that the gem may indeed be in a crypt in the 'Valley of the Sun' i.e. Sunnydale; Spike already found it and has dumped the childish Harmony.
Buffy makes love with her new crush Parker Abrams. Spike has returned to Sunnydale with Buffy's former classmate Harmony Kendall, presently his girlfriend, trying to find a powerful stone in an underground chamber. Anya also returns wanting to have sex with Xander. On the next morning, the relationships are broken and Spike faces Buffy by day.
- At the Bronze, while the Dingoes play on stage, Willow and Oz talk while Buffy secretively watches Parker play pool. After the Dingoes wrap, Oz gets ready to take Willow home and Parker volunteers to take Buffy back to her dorm since it isn't safe outside. While Willow is waiting for Oz and Devon to return to the van outside the Bronze, Harmony approaches her. The two of them talk and then Harmony reveals she's a vampire and bites Willow. Oz rescues her and Harmony goes away threatening that her boyfriend is not going to be happy that they were mean to her. Buffy and Parker walk back to the dorm, and Parker discovers her scar from when Angel bit her. She tells him it was an angry puppy that bit her. He then asks her to a party the next night and she accepts.
At Giles' place, Xander is helping him put books away when Anya makes a surprise visit. She wants to know where her relationship with Xander is going, and not aware that they even had a relationship, Xander is a bit confused. Back at the dorms, Buffy and Parker are just about to kiss when Willow and Oz arrive. While Oz cleans her wound, Willow fills Buffy in on everything, including Harmony's supposed boyfriend. Harmony goes to her boyfriend who's working underground and it's revealed to be Spike. He works on plans with another vampire to dig through the floor of a crypt. Harmony persistently annoys him and he continues to yell at her. She complains that she wants to go out, and after the use of some feminine charm, he agrees to take her out to a party.
The party happens to be the same one Buffy and Parker are attending and the two couples run into each other. A thoroughly amused Buffy teases Spike about being with Harmony and the two vampires flee. Buffy pursues them and she and Spike fight. Harmony reveals that Drusilla left Spike for a fungus demon and that they'll be back as soon as they get the Gem of Amara, to Spike's utter irritation. Anya shows up at Xander's place and after getting her a drink, he turns around to see that she's naked. Buffy calls Giles and informs him about Spike and Harmony. Giles looks up the Gem of Amara, and he says it doesn't exist. Buffy says she's going to sleep but instead, goes back to the party with Parker. Harmony annoys Spike then draws his full attention with her sexual charm. Anya and Xander have sex because she's convinced it will help her get over him, and Buffy makes the decision that she wants to sleep with Parker.
The next morning, Buffy wakes up to an empty bed, and as she's searching for her clothes, Parker arrives with coffee. He says that he'll call her. Anya tells Xander that she's over him, and when he says he's okay with that, she storms out in anger. Spike wakes up to Harmony drawing on his back with lipstick and then leaves to get back to work. Buffy finds Willow and Giles in her dorm room and apparently the Gem of Amara is real. After they get rid of Giles, Buffy tells Willow about her night with Parker.
Spike finally breaks into the crypt, and thinks he's found the Gem of Amara in a necklace. Harmony shows up and starts trying on jewelry. Spike finally loses his control and tries to stake her but the stake doesn't kill her. He sees the ring and after holding a cross to her, he takes the ring off of her and leaves to go outside. At Giles' place while they search for answers, Xander finds a TV and turns it on. They watch the news and see that there was a sinkhole caused by the erosion of dirt beneath it. They come to the conclusion that it was Spike's underground digging that caused it. Buffy tracks down Parker, but she finds him putting the same moves he used on her on another girl and that the sex they had was basically meaningless to him. She thinks it's her fault and again, feels sorry for herself. Spike shows up in the daylight and hits her.
Buffy and Spike have a spectacular fight outside. She tries to stake him, to no avail. Xander shows up but Spike quickly knocks him out of the way and continues to beat up Buffy. He talks very vulgarly about her relationship with Parker, with just enough truth in his comments to sting. Then Spike makes the mistake of bringing up Angel and mocking their relationship as well. An enraged Buffy pummels Spike and takes the ring from him. Smoking from exposure to the sun, he dives down into the sewers. Later, Buffy and gang sit around at Giles's place and Buffy decides that she wants Angel to have the ring. Oz volunteers to take it when he goes to LA for a gig.
Buffy, Anya and Harmony all walk separately around campus, all single.