Harry (Daniel Radcliffe) is about to spend his third year at Hogwarts when news spreads in Aztaban that villain Sirius (Gary Oldman) has escaped from prison. It is said that Sirius is a good friend who betrayed Harry's parents, his godfather, and Sirius seems to have escaped from prison to find him. The idea of avenging his parents quietly grew in Harry's heart, and he was looking forward to Sirius's appearance. The new magic teacher, Lupin (David Heuris), has a rebellious personality, has a good relationship with Harry, and has taught Harry a lot of practical knowledge on defense against dark arts. At this time, a mysterious character, Wormtail, appeared on his magic map. By chance, all Harry's father's friends from the past, Lupin, Wormtail, and Sirius, were gathered in the Screaming Shack. Harry pointed his wand at Sirius, but he noticed that the criminal was looking at him. It was full of love...