A nightly patrol begins as Buffy thwarts a mugging. From the darkness, Spike comes to the rescue. Unfortunately, the muggers are human and the chip impairs the neutered one. After the pain is relieved, Buffy and Spike rant briefly about their kisses. Once again, Buffy blows him off.
At the Slayer's home, Willow finds herself lonely without Tara. In an attempt for social contact, she transforms Amy "the Rat" Madison back to her human form.
At the Sunnydale Museum of Natural History, antics ensue as Warren, Jonathan and Andrew steal a diamond and freeze the security guard with their freeze ray.
Amy and Willow catch up and Amy finds out that she has been a rat for almost three years. Buffy returns home confused to find a rat-less Amy. Buffy intended to tell Willow about her two kisses with the Spikester, but the shock of seeing Amy makes her reconsider.
After seeing the frozen museum security guard on the news, Buffy rushes to investigate. To her chagrin, Spike is already there. After a heated exchange, Buffy slugs Spike and he hits her back. Strangely, the chip doesn't seem to affect him. He does, however, pretend to be in pain. Thinking that the chip has malfunctioned, Spike takes to the streets looking for Lunchables. After deciding on a victim, he dives in for a bite and the chip takes action.
Meanwhile, at the Magic Box, Buffy, Anya, Willow and Xander research the stolen diamond. After Willow browses through her computer using magic, Anya bravely scolds her for her behavior.
Looking for answers, Spike infiltrates the lair of the dork crew. Although they are reluctant to help, Spike convinces them by threatening their Boba Fett action figure.
Back at the Slayer's abode, Willow and Amy decide to go do something fun on the town.
After assessing Spike's chip, Warren tells him that it is not malfunctioning. Spike concludes that there is nothing wrong with him, but that there is something wrong with Buffy.
Across town at the Bronze, Willow continues to bring Amy up to date, when two young studs ask them to dance. The former rat jumps at the chance. A little later, when the two college guys forcibly try to get Amy back on the dance floor, Willow and Amy transport the two studs into go-go cages and skimpy outfits.
Down in Spike's crypt, the bleached bloodsucker prepares to stick it to the Slayer by pulling out several goodies, including a stun gun, a rope, chains, padlocks and handcuffs. Then, he puts on a Roxy Music record, lights some candles, sets up flowers and then puts rose petals on the bed. When he is content with his preparation, he bolts from the crypt in search of Buffy.
At the Magic Box, Xander, Anya and Buffy continue their detective work. Unable to find their baddie, their focus changes to Willow. Their concern is evident as Anya warns that once someone good gets a taste of bad that it's difficult to bring them back. Suddenly, Spike calls, inviting Buffy to the cemetery. At first she declines, but after Xander and Anya head home for the night, the trench-coated vamp appears from the shadows. He stands in front of Buffy, not letting her pass. She smacks him. To her horror, Spike hits her back. Unaffected by the chip, Spike explains saying, "Don't you see? You came back wrong." Immediately, a scrap breaks out.
At the Bronze, Willow and Amy continue generating havoc. As Willow turns a boy band into a girl band, people are dancing aimlessly in elaborate outfits and mutate.
The brawl continues between Spike and Buffy at a condemned house, the Slayer and the Vampire are knocking the structure, as well as each other, all over the place. Suddenly, Buffy pins Spike against a wall and begins kissing him. As they engage in their most passionate make out session to date, the house crumbles all around them and they fall through the floor.
Summary from Buffy.com