In Harry Potter's third year at Hogwarts, he faces a new challenge when a notorious prisoner named Sirius Black escapes from the magical prison of Azkaban, supposedly targeting him. As Harry adjusts to school life, the mysterious Dementors, creatures that guard Azkaban, begin to haunt the castle, affecting all the students. The atmosphere grows darker, and Harry feels an inexplicable connection to Sirius, the figure everyone fears.
As the year progresses, Harry, along with his friends Ron and Hermione, stumbles upon secrets about his family and his past. Hermione stands out this year with her use of the Time-Turner, a magical artifact that allows her to attend more classes, although this leads to complicated situations.
The plot becomes filled with surprising twists as hidden truths are revealed: Sirius is not the villain everyone believes him to be, but rather a key figure in Harry's life. Together, they uncover the betrayal behind Harry's past and the true culprits of his parents' death. Using the Time-Turner, Harry and Hermione make risky decisions to change the course of events.
With an ending full of action and emotion, friendship and courage shine brighter than ever, leading Harry to confront his fears and accept that not everything is black and white in the magical world.