Unfortunately, before long, Aurors from Azkaban arrived at Hogwarts with Dementors in tow!
What happened afterward differed little from the original story.
Harry won the Quidditch match, but the Dementors stirred up his deepest fears. He got the Marauder's Map from the Weasley Twins and discovered that Peter Pettigrew had actually appeared on it.
Then a series of events brought the Main Character Group face-to-face with Lupin and Sirius, revealing the truth about what had happened all those years ago.
As it turned out, Sirius had never become one of Voldemort's Death Eaters. He had not betrayed Lily and James, nor had he killed Peter Pettigrew.
After a bout of frenzied behavior, they pointed out that Ron's pet rat, Scabbers, was Peter Pettigrew.
At first, the three members of the Main Character Group did not believe them, but... Scabbers bit Ron's arm, and while fleeing, he was struck by a spell and suddenly turned into a human.
His fat body got stuck in the fireplace. He wept and begged them to forgive him, only to resort to dirty tricks and escape while they hesitated.
Immediately afterward, Lupin transformed into a werewolf. He lost his senses and began attacking indiscriminately. Sirius turned into a large dog to fight him, but... he was no match!
At Dumbledore's prompting, Harry and Hermione used the Time-Turner pocket watch to return to the past.
Working together, they changed the outcome.
And through this, Harry summoned his Patronus—a doe—and found his closest family member, Sirius.
However, because Peter Pettigrew had escaped, Sirius still had to bear the blame. With Dumbledore and Hagrid's tacit approval, he rode away from Hogwarts on the Hippogriff Buckbeak.
Before leaving, he promised Harry that he would find a house to be their home, so Harry would no longer have to stay