Hermione Granger completing Snape's homework assignment from the class, while Crookshanks proves vital in exposing Scabbers as Peter Pettigrew, a friend of James and Lily Potter who revealed their whereabouts to Lord Voldemort the night of their murders, and was able to wrongly implicate Sirius Black (revealed to be Harry's godfather) in the Potters' deaths. The Time-Turner enables Hermione and Harry to rescue Sirius and the hippogriff Buckbeak. Hermione is horrified by the cruelty that house-elves suffer, and establishes S.P.E.W., the Society for the Promotion of Elfish Welfare, as an effort to gain basic rights for them. She is Bulgarian Quidditch prodigy
Hermione Granger is the best student in Harry's year and is repeatedly the first student to master any spell or charm introduced in classes and even from more advanced years, as evidenced when she is able to conjure a Protean Charm on the D.A.'s fake Galleon coins, which is actually a N.E.W.T. level charm. She is also the first one to be able to cast non-verbal spells. Hermione is a competent duellist - Rowling has stated that while during the first three books Hermione would have beaten Harry in a magical duel, by the fourth book Harry had become so good at