Escape from Azkaban
It had been 12 years. Sirius Black sat in his Azkaban cell feeling terribly bored.
Apparently, the Minister was coming today for some reason he (nor the man 2 cells down) didn't know. Not that Sirius especially cared; the Minister was most likely a git anyways.
He leaned back and stared at the cell door ahead. Suddenly, he stiffened. A voice could be heard down the corridor. Not screaming inmates, but a man who he presumed to be the Minister.
"…mad, the lot of them. All darting eyes and mumbling nonsense. Awful place."
Black robes came into view. There he was, the Minister of Magic himself. "Hello there." Cornelius Fudge stood before him, gazing jadedly at him as if he expected him to be just like the other barmy inmates he described.
For a brief moment, Sirius felt annoyed. Then he decided to be civil. "How do you do, Minister." Sirius felt a rush of amusement as Fudge took on perhaps the most gobsmacked face he had ever seen. "Ooh! A sentence!" the Minister then looked horrified at himself. "I'm so terribly sorry, I just didn't expect-" "Anyone here to be able to form coherent sentences." He smiled mirthlessly. "Unfortunately, yes, that is what I've come to expect. Sad place, this." The Minister then added; "You don't seem too affected by them" he said with a hint of suspicion in his voice.
Sirius shrugged, and then noticed a newspaper poking out of the Minister's robe pocket. "You done with that paper?" he asked, eying it hopefully. It had been so long since he had known what was happening in the outside world. Fudge nodded and handed it to Sirius. His bony hands grasped the paper excitedly. "Thank you for your time, I really must be off now." Fudge said awkwardly. Sirius nodded absently. "Take care."
He read slowly, trying to savor the paper as much as possible. Every little bit of news seemed exciting compared to the hellhole he lived in. A crime committed! A cure discovered! An annual grand prize won! Sirius stared at the photo of the waving, smiling family. He felt a small prick of jealousy at how happy they were. All together, look, they even had their pet rat.
His eyes bugged out, and he couldn't breathe. He knew that rat. He had spent many full moons out at night with that rat. That fat, ugly rat was none other than Peter Pettigrew. Sirius drew in a long, shaky breath. He was with this family. He would pay for what he did to Lily and James. Not a day had gone by where he didn't miss them. He would avenge them, and do what he had been imprisoned 12 years for.
The next week he spent thinking up dementor's weaknesses and escape plans. Sirius soon found this newfound obsession cleared his head. Even his dreams here about Pettigrew and escaping. It was like someone had lit a fire in his head. The fire wasn't happy, but it gave him strength, and the bloody dementors couldn't suck that out of him. Peter had been living in Animagus form. How irritatingly ironic. Maybe he could use his Animagus form to his advantage! As a dog, he would be thinner, faster and have the element of surprise. Animal emotions also aren't as complex as human emotions, so the dementors would merely think he's going mad, therefore they will underestimate him and not expect an escape. Dementors are blind, so they only sense emotions. If Sirius was to somehow escape as a dog, that would work!
He grinned. He decided that when they fed him, he could slip out the crack in the door, run like the dickens and swim to the mainland. It was crazy, very dangerous, but ingenious, if he didn't say so himself.
He could sense the dementor a few cells down. He immediately transformed, then waited. He tried not to think about what would happen if he was caught. The dement- no. Worrying would mean suffering twice. This was too important to mess up.
About a minute later, his door opened around 6 inches. He lunged forward, hurtling through the tiny crack. He barely heard the confused shouts of fellow inmates. The cold presence turned to towards him, but he was long gone. He barreled towards the water. Sirius jumped in and swam fast as he could; triumphant, ecstatic and in shock at his success. He began thinking gleefully of all he could do with his new freedom. He could see his godson, visit Hogwarts and Godric's Hollow, see old friends, and rid the world of a rat.
After a long time, he arrived at the mainland. He transformed back into human form, utterly exhausted. He surveyed the lush green grass and hills ahead with a small smile. Then, for the first time since he had been arrested those 12 years ago, Sirius let out his signature barking laugh.