Chapter 11 - "Quidditch" - In which Snape takes Harry's book, leading to Harry seeing Snape's injured leg. Harry's first [Quidditch] match against Slytherin in which someone jinxes his broom but he catches the Snitch and wins anyway. Hagrid later lets a secret slip.

Halloween and the Troll
A group of Hogwarts teachers rushes in to find the troll knocked out, and Hermione lies about why the trio was going after it. Professor McGonagall takes points away from her, but awards points to Harry and Ron for saving her and knocking it out.
Harry, Ron, and Hermione walk back up to Gryffindor Tower in silence, and before heading to bed say a quick "thanks" to each other, sealing their friendship.
As time passes and the first [Quidditch] match approaches the weather cools, Gryffindors cheer and jeer Harry about the upcoming match, and Hermione loans Harry [Quidditch Through the Ages].
Snape spots Harry with [Quidditch Through the Ages] and nastily takes it from him and, Harry notices, limps away across the courtyard.
A restless Harry decides to try to find Snape and get his book back, but accidentally walks in on Snape and Filch binding Snape's injured leg and talking about the three-headed dog, convincing Harry and Ron (but not Hermione) that he's trying to get into the [third-floor corridor].
Harry's First Quidditch Match
On the morning of his first [Quidditch] match, Harry sits at breakfast but is unable to eat anything out of nerves.
The Gryffindor and Slytherin [Quidditch] teams prepare for their first match - Hermione, Ron, and the Gryffindor boys settle into the stands, Harry listens to [Oliver Wood]'s speech, and Madam Hooch asks for a clean, fair game before blowing the whistle.
The first [Quidditch] match of the year begins: Lee Jordan calls the match, Hagrid arrives to sit with Ron and Hermione, and Harry's broomstick suddenly begins acting up. Hermione, thinking it's Snape's doing, sets his cloak on fire, and Harry recovers just in time to catch the Snitch in his mouth and win the match.
Harry, Hermione, and Ron sit in Hagrid's hut after the [Quidditch] match, celebrating Gryffindor's victory and discussing Snape, Fluffy, and thanks to a slip-up from Hagrid, Nicholas Flamel.