Deep in concentration during a training session at Giles' house, Buffy executes a very difficult one-handed handstand. Below her lies a neatly stacked pile of crystals. Dawn, Buffy's newly arrived younger sister, carelessly adds another crystal to the pile, causing them to topple. This disrupts Buffy's concentration and she falls flat on her back. As a surprised Buffy looks up, Dawn asks smartly if they can leave. Back in her room, Dawn writes glumly in her journal. Suffering from a major case of sibling rivalry, she writes that no one knows the real her and that no one understands what it's like to have a slayer for an older sister. She surmises that she too could save the world if she were handed Buffy's superpowers. The next morning, Joyce, Buffy and Dawn eat breakfast in the kitchen. Dawn cunningly takes Buffy's bowl of cereal along with the last of the milk, annoying Buffy to no end. As if things weren't bad enough, Joyce suggests that Buffy take Dawn to the mall to get her back-to-school supplies since she'll be going to the magic shop with Giles. Just as Buffy grudgingly agrees, Riley drops by. Dawn expresses her disgust for Riley in her inner monologue and storms out the kitchen. Realizing that she had forgotten her previous plans with Riley, Buffy agrees to meet with him later. As Giles, Buffy and Dawn ride down the street in his sporty new car, Dawn spots Willow and Tara, so they pull over. In her journal, Dawn writes about how she really likes Willow and Tara because they are witches, and that casting spells is much cooler than slaying. Willow is happy that Buffy is developing a work ethic with the slayer training but is upset that Buffy has to drop the drama class they're both in. As the gang approaches the magic shop, things don't look right. When they enter, they notice that the place has been ransacked, and Willow trips over the body of the storeowner. Buffy leads an unwilling Dawn out of the store before she sees the body and tells her to wait outside. While Dawn tries to peek through the blinds from the outside, a weird, disheveled man approaches her and asks her what she's doing. Just as Dawn is about to yell for Buffy, he quiets her and tells her that he knows her, knows what she is and that she doesn't belong there. Inside, Buffy and Giles agree that judging by the bite-fest on the victim, more than one vampire was present for the attack, which means that there must be a new fang club about. Willow informs Buffy and Giles that some of the inventory is missing, mostly books including one about the methodology of the vampire slayer. While Buffy is upset about missing a book she was after, Giles is more concerned that there is a pack of vampires interested in learning more about the Slayer, but his attention is diverted when he examines the store's ledger and notices how high the profit margins are. Giles then discovers a shattered showcase and wonders what item was taken. Willow informs him that it was a cheap, ceramic unicorn. As they all agree that the next step would be to find the lair, Giles wonders what kind of unholy creature would fancy a cheap, tasteless statuary. Deep in her lair, Harmony congratulates her minions for a successful raid on the magic shop and is touched that someone brought her back a cute, ceramic unicorn. She tells her vampire minions that the books will help them carry through with their plans to kill the Slayer later on that night. The vampires look satisfied. Back at the house, Joyce berates Buffy for bringing Dawn to a murder scene, and accuses her of wanting to dump Dawn off so that she can go out with Riley. Buffy reminds her that she and Riley are going to patrol, not party. Dawn protests against needing a babysitter until she hears Joyce and Buffy agree on letting Xander babysit. As Joyce leaves, a dressed-up Dawn answers the door for Xander, who comes bearing pizza. Just as a smitten Dawn is about to close the door, Anya bursts in with a bunch of board games. Out on patrol, Buffy rants to Riley about how Joyce expects her to coddle Dawn. Riley comments that Buffy seems to be a little too hard on Dawn. Meanwhile, Dawn does some ranting of her own to Xander and Anya, when a brick crashes through the living room window. Attached is a note that reads "Slayer, come out and die." Xander quietly peers out the front door and sees Harmony and her gang. He mockingly informs her that Buffy is not home and she and her buddies will have to come back later to be killed by Buffy. Harmony reaches for Xander, and realizes too late that she has not been invited in. Frustrated, Harmony begins a war of insults that draws Dawn in, trying to defend her precious Xander. Without thinking, Dawn yells out for Harmony to come inside so Xander can kick her butt. Anya tries to stop Dawn from interfering, but it's too late. Harmony storms in and knocks Xander to the floor. While Xander struggles with Harmony, the other vampires try to enter through the door but bounce off of the protective field. Xander manages to kick Harmony back through the front door and shuts it, locking her out. Harmony yells out that she will be back and Xander assures her that they will be ready. Later on that night, Xander informs Buffy of Harmony's plans to kill her and that she can get into the house thanks to Dawn's invite. Buffy is furious, but Xander defends Dawn by telling her that was an accident. Meanwhile, while Harmony and her minions make their way back to her lair, they get a surprise visit from Spike. After hearing Harmony's story, Spike is surprised to hear that she has her own gang and plans to kill the Slayer, but he warns against it, telling her to leave it up to the professionals. She vows that Buffy will be dead before sunrise and to kill everyone that was ever mean to her in Sunnydale after Buffy is dead. Back at the house, Buffy prepares her weapons and complains about how Dawn gave Harmony a backstage pass to kill them all in their sleep. Xander tries to defend Dawn as Dawn secretly listens in, but Buffy's continuous tongue-lashing of Dawn sends Dawn running out of the house crying. Anya sees her and runs out after her, but is too late. One of Harmony's minions knocks Anya out and takes off with Dawn. Later that night, Buffy bursts into Spike's lair to get information on Harmony, and he gives it up after a few punches to the face. Back at Harmony's lair, Harmony congratulates her minions on a job well done. They want to feed on Dawn but Harmony won't allow it. Harmony tells a chained-up Dawn about how her gang doesn't respect her and treats her like she doesn't even matter. She asks Dawn if she knows what that feels like and Dawn responds that she does. Just then, the gang walks in and tells Harmony that they don't like her plan. They have a plan of their own: kill her and eat Dawn. One of the vampires grabs Harmony by the throat as another approaches Dawn. Dawn warns the vampire that if he touches her, her sister will kill him. Not frightened at all, he laughs and pokes her on the shoulder. As the other vampires laugh at his mocking gesture, a stake flies into chest, turning him into a cloud of dust. Buffy appears and tells Dawn to close her eyes. As Buffy quickly takes care of the vampire gang and unties Dawn, Harmony sees her chance and makes an escape. Back at the house, Dawn and Buffy tell Joyce that everything went smoothly. The next day at the magic shop, Dawn writes in her journal that everything seems to have worked out okay - Anya is going to be fine and Xander isn't mad at her. Meanwhile, as Buffy and Giles look through boxes, Buffy asks Giles if he's sure about being the shop's new owner since the life expectancy of magic shop owners in Sunnydale is so short. He says that he was a librarian for years and it's not much different except that people pay for the things they are not returning. When Giles and Buffy go into the back to see if there's enough space to do their training, Buffy comes back and warns Dawn to not break anything. She leaves and comes back again to tell her not to touch anything. She comes back one more time to tell Dawn that not doing anything would be good. Dawn rolls her eyes and writes that Buffy still thinks of her as her dumb little sister, and that she is in for a big surprise...