Chapter 10 - "The Marauder's Map" - In which Harry spends the weekend in hospital, Lupin returns to class and tells Harry about dementors, and Fred and George give Harry the Marauder's Map. Harry uses a secret passage to join Ron and Hermione in Hogsmeade, they overhear a teachers' conversation, and learn that Black is believed to have betrayed Harry's parents and is his godfather.
The Loss of a Faithful Broom
Harry awakens early to Peeves blowing in his ear, and trudges down alone to the common room, stopping en route to prevent Crookshanks from sneaking into the dormitory, and sits alone thinking about the game.
The [Gryffindor Quidditch team] heads out to its first match in torrential rain, with [Oliver Wood] barely able to speak a word pre-game. Harry can barely hear Madam Hooch, but nevertheless sees her whistle - and the match begins.
The [Quidditch] match between Gryffindor and Hufflepuff is a challenging one - in the heavy rain Harry doesn't even know the score. Hermione helps him clear his glasses during a time out, but just when he sees the Snitch, Harry also sees over a hundred [dementors] - and, after hearing his parents' dying words, blacks out.
Harry wakes up in the hospital wing, surrounded by his teammates and Ron and Hermione. He learns that Gryffindor has lost the match, that [Dumbledore] saved his life, and that his Nimbus 2000 blew into the Whomping Willow after he fell and was destroyed.
Staying in the hospital wing for the weekend, Harry has a slew of visitors, from Ginny bearing a homemade get well card to the [Gryffindor Quidditch team], as well as Ron and Hermione. The whole time, however, Harry is worrying about the Grim, and about his reaction to the [dementors].
A Conversation with Lupin
With Lupin back in Defence Against the Dark Arts, the class launches into a tirade on Snape's behavior filling in as their teacher, and Lupin stands by them, cancelling the homework, and then proceeds to teach about [hinkypunks].
A Gift From Fred and George