Sunset
Hogwarts was, as always, a home to return to. Sirius packed his luggage with a swap of his new wand, then stepped to the window to bask in the late afternoon's golden light. His motorbike looked slightly out of place on the magnificent castle's balcony, but as long as the electric ignition was properly shielded from the magical aura disabling most muggle-made devices, its owner didn't worry. Not about his flying vehicle.
During last full moon, Severus Snape had substituted the "sick" Remus Lupin, then talked about werewolves and ways to fight them. This time Moony had made sure he'd leave the children in proper hands: he'd asked Padfoot to replace him for the three days as a Defense teacher for all the classes, third-year Gryffindor included. He'd be teaching Harry - that was an unbearably happy thought.
As he would be formally introduced only at dinner, Sirius decided he wouldn't run off to see his godson immediately. He didn't even know if James's son wanted to see him. He was just a recently released prisoner, trying to catch up with twelve years' worth of history.
Instead of running to the Gryffindor tower, he decided to spend the rest of the day at the library, seeking knowledge for future use. Azkaban had been found by the British Ministry of Magic in the fifteenth century, after the death of the dark wizard Ekrizdis, and by that time dementors were already there. This much was available knowledge. But he didn't know how they had been then bound in the Ministry's servitude, or how Ekrizdis had trapped them on the island, in the first place.
Padfoot's fingers curled around his wand: teakwood with Daire's gift as its core. Poor Garrick Ollivander had been aghast when he had received the parchment-thin, green skin-piece that had come off a dementor's hand. The wandmaker had repeatedly warned Black that he takes no responsibility for the new wand's behavior. But when he had finished his work, his sole comment was "Do not try conjuring a patronus with it."
Sirius took one last glimpse at his motorbike parked just outside his room, then headed straight to the library.
He had only found a young Gryffindor witch at the central table, barricaded with a rune dictionary, an arithmancy textbook, and a copy of Lyall Lupin's guide to non-beings. He didn't want to disturb her, but the witch looked up from her reading. After a quick introduction, she asked if he knew what was wrong with her professor. Sirius tried to laugh the question off.
"He's been like this ever since I've met him."
Sirius was prepared for funny looks, but she only thanked him, and turned back to her readings. He was shocked to find she was looking up dementors in the guide, and writing a list of questions.
"What's not in the book, that one or any other," he noted, seeing the first line, "while they are usually foul, they're not nearly as bad as some wizards are."