Harry Potter and the Prisoner of Azkaban

When a visit by Aunt Marge to visit the Dursleys goes horribly wrong - Harry accidentally causes her to blow up like a balloon - Harry takes off. Whilst Harry is scared he's going to be expelled, the Ministry are more worried that he's going to be knocked off by the notorious prisoner, Sirius Black who has escaped from Azkaban and appears to be on his way to find Harry. Back at Hogwarts Harry discovers both that Sirius is his godfather, and that it was Sirius that blabbed to Voldemort the location of his parents. But all is not what it seems and in seeking to expose Sirius, Harry and his friends discover the truth. With the help of a time turner, Harry and Hermione travel back to the past to help themselves in a daring rescue. Can they do it, or will the universe collapse? Strange things happen when you mess with time!