chapter 10-the Marauder's map

Ok so this has been a long chapter but its almost over :) so Harry, Ron and Hermione decide to go to the Three Broomsticks for some Butterbeer and all of the sudden, all of these teachers come in and start talking about Sirius Black and how he's Harry's godfather.  Supposedly Sirius was the secret-keeper for the Potter family and he betrayed them.  I know thats not the truth though.