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
Harry Potter and the Half-Blood Prince continue. Harry finds out that the locket is not the real Horcrux, containing only a note from someone named "R. A. B.". Harry is so devastated by Dumbledore's death (and upset by its futility) that he tells his friends he will not be returning to Hogwarts. Instead, he will spend the next year searching out Voldemort's Horcruxes. Ron and Hermione insist on joining him in destroying Lord Voldemort for good. "Harry Potter and the Half-Blood Prince" is the sixth book in the Harry Potter series. The first book in the series, "Harry Potter and the Philosopher's Stone", was first published