Chapter 19 Summary

Professor Snape seems to be in some mad trance. He is so bent on satisfying a schoolboy grudge that he will not listen to reason at all. He only wants to take Black and Lupin to the Dementors. He ties Lupin up with cords that shoot from his wand and tries to leave the Shack with Black and Lupin. Harry tries to stop him, but he is more vicious than ever; calling Harry an arrogant boy who is just like his father.

Harry, driven by frustration, puts the disarming spell on Snape. At the same time, so do Ron and Hermione. Snape is knocked into the wall and passes out. They untie Lupin and Harry asks for the rest of the story. Black explains that it was not Peter who hunted him down on the night Harry's parents were killed; it was the...