This chapter is about Draco being expelled from Hogwarts after insulting Buckbeak. After all, it wasn't Hagrid's fault. He had made it crystal clear to not insult hippogriffs or else they will attack.
When Draco was walking back to the Slytherin common room, he walked across McGonnogal. McGonnogal said sternly, "Draco, I want you in my office. Please come to my office right now."
Draco asked, "Why? What do you even need me for?"
McGonnogal spoke with a clear voice, "I said, COME. Just do as you are told to do so." Left with no choice, Draco dragged his footsteps and followed McGonnogal to her office.
Once they reached her office, McGonnogal said, "Sit down." Draco did as he was told to do so. McGonnogal continued, "Draco, I brought you here to tell you, that you are no longer a student in Hogwarts anymore. You are expelled because you insulted Buckbeak despite Hagrid's clear warnings saying not to do so. Now tell me, why did you insult Buckbeak?"
Draco snarled, "Why am I getting expelled just for that? And also, Harry Potter could ride the hippogriff, so that's why I insulted it."
McGonnogal replied, "Well, you are a lunatic. Just because you don't like Harry, and he could ride the hippogriff, then you went on to insult it. Well, it serves you right, you just got your fate and got your arm injured. Hagrid is so distressed right now and it is all because of you. Too bad, you are expelled from Hogwarts. You and Lucius will not come back to Hogwarts ever again. Go and pack up your things right now. I am being serious. GO NOW!" Fuming, Draco walked out of her office and went to pack his things. After this day, Draco never ever returned to Hogwarts ever again.