Harry Potter (Daniel Radcliffe) is waiting for the summer holidays to end so that he could leave his aunt's home and get back to Hogwarts. Uncle Vernon's (Richard Griffiths) sister Marge (Pam Ferris) comes home and insults Harry's parents. Without meaning to, Harry manages to inflate Aunt Marge who floats up to the ceiling. Running away from home, Harry gets into the Knight Bus that takes him to...

Harry Potter (Daniel Radcliffe) is waiting for the summer holidays to end so that he could leave his aunt's home and get back to Hogwarts. Uncle Vernon's (Richard Griffiths) sister Marge (Pam Ferris) comes home and insults Harry's parents. Without meaning to, Harry manages to inflate Aunt Marge who floats up to the ceiling. Running away from home, Harry gets into the Knight Bus that takes him to the Leaky Cauldron. He meets Cornelius Fudge (Robert Hardy), the minister for magic. Fudge reassures Harry that he would not be expelled from Hogwarts for performing magic. Harry also finds out that Sirius Black (Gary Oldman), the convict, has escaped from the wizard prison Askaban. He is Voldemorte supporter. Everyone's convinced that Sirius Black will come to get Harry. Will Harry survive?