Ron was adamant that Hermione was the human version of Mrs Norris.
Next morning Malfoy was amazed to see that Harry and Ron hadn't been expelled. Unfortunately for Harry, Hedwig brought him a letter from home; 'Harry' it said, he recognised his mother's handwriting 'I know you'll be mad at Hermione for writing to us but it is the right thing to do. Harry no matter what the reason is don't get out of bed after hours. I don't want you to turn into your father. All my love. Lily.' Harry screwed the letter up angrily.
That evening when Harry walked in, Hermione was hiding behind a pile of books. Harry was so mad at Hermione that he didn't know what to say to her or Ron so he ignored them both and went straight up to bed. Next morning he was still angry, he told Ron what happened after their charms lesson, who called Hermione some very rude and nasty things. Harry noticed Hermione walk by crying her eyes out. "I think she heard you" Harry felt guilty but Ron seemed unrepentant.
Hermione was washed clean out of their minds when they saw the Halloween feast. A little ways into the feast Professor Quirrel came running in shouting "TROLL! TROLL IN THE DUNGEON" and he fainted. There was bedlam. Then Dumbledore told them all to go to their dormitories. Half way there Harry realised that Hermione didn't know about the troll. As they ran to find her they accidentally locked her in with the troll, they rescued her from it and McGonagall awarded them 5 points. After that Hermione became their friend.