Time rushes by uneventfully at Hogwarts. Harry avoids Gilderoy Lockhart and Colin Creevey as much as possible, and Ron's wand continues to muddle spells. Early Saturday morning, Harry is shaken awake by Oliver Wood, the captain of the Gryffindor Quidditch team, for a crack-of-dawn practice. Harry dresses quickly and on the way to meet the team in the locker room, runs into Colin, who eagerly asks him to explain the rules of Quidditch, which he does. The game's basic terms are this: the game is played with seven people on broomsticks, and during it the small golden Snitch flies around and must be caught by the Seeker (Harry's position) in order for the game to end. Two Bludgers fly around, trying to knock the players off their broomsticks, and two team members, the Beaters (Fred and George Weasley), try to beat the Bludgers away. Other than this, the game is similar to water polo, in that the remaining three members, the Chasers (Alicia Spinnet, Angelina Johnson and Katie Bell), aim to throw a ball, the Quaffle, through the goal posts and past the Keeper (Oliver Wood).
The team spends a long time in the locker room, listening to Wood explain moves. Finally, they head outside to practice and are greeted by Ron and Hermione and Colin Creevey, all watching from the bleachers. Colin is taking pictures and calling for Harry to look over and smile, and Harry is embarrassed and pretends not to know him.
Wood is beginning to grow suspicious that Colin is a spy for Slytherin. Slytherin's team enters the field, interrupting the practice and infuriating Wood, who had reserved the field already. The Slytherins refuse to leave, claiming that they must train their new Seeker. Draco Malfoy steps up, smirking and explaining that his father made a generous gift of seven top-notch broomsticks to the team. He makes several disparaging remarks about Fred and George's rather tattered broomsticks, and Hermione steps in and remarks that at least Fred and George were talented enough not to have to buy themselves onto the team. Malfoy gets angry and calls Hermione a "Mudblood," a word that causes the crowd to gasp and Ron to pull out his wand and cast a spell on Malfoy. Ron's spell reverses, causing him to belch slugs.
Hermione and Harry take Ron to Hagrid's cabin, where Lockhart is bidding adieu to a rather sullen-looking Hagrid. Hagrid cheers up when he sees the students, and he offers Ron a basin for his slug-belching, remarking cheerfully, "Better out than in." The students recount the story and Ron explains that Mudblood is a terribly derogatory term for a Muggle-born wizard. Hagrid soon changes the subject, and asks Harry for an autographed photo. Harry bristles until he realizes that Hagrid was joking. Hagrid shows off his magic-enhanced pumpkins, although Harry knows that ever since Hagrid was mysteriously expelled from Hogwarts and left to remain as gamekeeper, he is not allowed to use magic.
Harry and Ron are called to do their belated detentions for the flying car incident. While Ron is called to help the grouchy caretaker Filch polish trophies, Harry is called to help Lockhart answer his fan mail. Both boys believe they have the worst end of the deal. In Lockhart's office, as he is addressing envelopes and inserting signed photos, Harry hears a high, eerie voice murmuring, "Come to me .let me rip you .let me tear you " and he jumps up, alarmed. He is alarmed further when Lockhart claims to have heard nothing. The thought of this chilling voice plagues Harry for the rest of the evening.
This chapter elaborates upon bigotry that is evident in the wizard world every time the Malfoys enter the scene. Pure-blood wizards are snobbish toward those who are Muggle-born, of one race or class trying to wipe out the next. Draco Malfoy turns on Hermione for her Muggle heritage and Ron Weasley for his family's meager finances, and Hermione's response that at least the Weasley twins had enough talent to play Quidditch without having to buy their ways onto the team, hits Malfoy in a vulnerable spot. He places so much pride on the fact that he can afford to lean back on his family's status and money without having to do anything to deserve it, that when Hermione points out that he does not deserve much of what he gets, he is upset. Malfoy picks on Ron for his poverty, Hermione for her heritage, and Harry for his fame. However, at different points in the story, he envies much of what they have: in chapter four, Malfoy complains to his father about Hermione's grades being higher than his, and about Harry being so famous and getting to play Quidditch. Succeeding at Quidditch, school grades, and fame requires competency, talent and a work ethic. Malfoy lacks all three, and he knows it.
The voice that Harry hears in Professor Lockhart's office is the first clue of the conflict to come. Harry hears an eerie voice that nobody else can hear, and at this point it is left to the reader to try to guess at the source of the voice. This is perhaps the first tangible sign that something is very wrong at Hogwarts.