Hermione Granger is crucial to Harry and Ron in their successful mission to solve the mystery of the Chamber of Secrets. Hermione is revived after Harry kills the basilisk, but she is distraught to learn that all end-of-year exams have been cancelled as a school treat. Hermione buys a cat named Crookshanks, who takes to chasing Ron's pet rat, Scabbers. Before the start of term, Professor McGonagall secretly gives Hermione a Time-Turner, a device which enables her to go back in time and handle her heavy class schedule, though this is not revealed until the penultimate chapter. Much tension comes into play
Harry Potter and the Prisoner of Azkaban Harry Potter and the Prisoner of Azkaban Harry Potter and the Prisoner of Azkaban is a fantasy novel written by British author J. K. Rowling and the third in the "Harry Potter" series. The book follows Harry Potter, a young wizard, in his third year at Hogwarts School of Witchcraft and Wizardry. Along with friends Ronald Weasley and Hermione Granger, Harry investigates Sirius Black, an escaped prisoner from Azkaban who they believe is one of Lord Voldemort's old allies. The book was published in the United Kingdom on 8 July 1999 by Bloomsbury and in the United States on 8