Chapter 30 - "Grawp" - In which Harry recalls the dream again, the Gryffindors play Ravenclaw for the final match of the Quidditch season, and Hagrid introduces Harry and Hermione to his half-brother, Grawp, making them promise to look after Grawp if he has to leave. Gryffindor wins the match and the Quidditch Cup, and Ron is carried triumphantly off the pitch.

Harry Desires to Speak to Sirius
Hermione spends [Defence Against the Dark Arts] trying one final time to dissuade Harry from breaking into [Umbridge's office], but as class ends and Umbridge goes running off toward the distraction, Harry makes up his mind and heads off to do it anyway.
With his nerves almost at a standstill, Harry breaks into [Umbridge's office] and uses the [Floo] to talk to Sirius and, as it turns out, Lupin. He asks about James and they discuss Snape's memory for a bit, along with the fact that Snape is no longer teaching Harry [Occlumency], until finally Harry hears footsteps and has to go.
Fred and George Bid Farewell
Harry hides under his [Invisibility Cloak] as Filch rushes in to get an "Approval for Whipping," presumably for Fred and George. Once he rushes back out, Harry slips out of the office as well, and heads toward the noise in the [entrance hall].
In the [entrance hall], Harry finds [Umbridge] confronting the [twins] for creating a swamp in a school corridor. Just as she and the Inquisitorial Squad rush in to capture them though, the twins [Summon] their [brooms], kick off into the air, give a quick plug to their joke shop and a quick good-bye to Peeves, and zoom off triumphantly into the sunset.
With Fred and George gone, their departure from [Hogwarts] quickly becomes legendary. [Umbridge] is unable to remove their [swamp] so it remains behind, and students quickly get out of control, using [Skiving Snackboxes] to skip classes and jinxing members of the Inquisitorial Squad. Meanwhile Peeves causes even more mayhem, aided and abetted by the staff.
In Charms class, Hermione wonders whether she should admit her knowledge about [Montague]'s disappearance and subsequent confusion, Ron worries about his mom's reaction to Fred and George's leaving Hogwarts, and Harry admits that he gave the twins the seed money to start their new [joke shop].
Hermione once again questions Harry on his [Occlumency] lessons, leaving him feeling guilty, but nevertheless wanting to continue his dreams and find out what's behind the door of the [Department of Mysteries].
The Quidditch Final and Grawp
The final [Quidditch] match of the season approaches, with Ron seeming more confident than ever, and Luna sporting a dramatic eagle hat.
The Gryffindor-Ravenclaw [Quidditch] match begins, to determine the winner of the [Quidditch Cup]. Partway through, though, Hagrid interrupts Harry and Hermione, asking them to follow him away from the game.