Disclaimer: Not my characters. Also not for profit.
Notes: Apparently I've found my niche in HP fic - it's very short and ambiguous stuff about Sirius and Remus. Not that I'm surprised.
Tides
Even Muggles, they said, knew that animals could sense the movings of nature, predicting earthquakes and storms and fires while ordinary humans had no warning. What Muggles lacked the sensitivity and understanding to discern, however, was that animals were more finely attuned to nature and the cycles of life than they realized. Some had theorized that this was a factor in the transformation of lycanthropes.
Or so Remus had said. Sirius hadn't been paying attention when they covered it in class, but he listened just fine to what Remus told him about his condition.
A dementor's long robes swished outside the bars of the cell, but Padfoot was huddled in a ball, dark tail curled almost to his nose, as he listened to the songs that nature sang to him from a distance, songs of chill mist and choppy waves and the tide. It was the night of the full moon.
His ears swiveled, and instinct caused his head to rise towards the spot where the moon must be in the sky; even deep within Azkaban, he could feel it pulling at his blood. He'd felt that pull so many nights, as he transformed and watched as his friends did likewise - he still associated it with the rush of rebellious delight that came from doing something they weren't supposed to do. Something they weren't even supposed to be able to do. This pull had accompanied him on nights of laughter and adventure and danger, and he had grown on him until it was nearly an addiction.
Feeling it now was bittersweet. Even in his canine form, he could not forget. He would never again see those magnificent antlers sprout as Prongs rose up before them. And Wormtail's little feet scampering whimsically through the grass... well, even if he could hear it again, it wouldn't be whimsical anymore.
And Remus... poor Remus.
James was dead. Because Peter had betrayed him, then blown himself up. Sirius himself was locked here in Azkaban, having been framed for his murder.
Which meant that Remus was out there somewhere, left all alone to endure the painful transformation he used to endure before they'd become Animagi. Sirius remembered perfectly well how Remus had spent mornings in the infirmary getting patched up every month, which had puzzled him until he and James had figured it out. He remembered the cuts and scrapes and gashes he'd seen. Remus was out there now, doing it again, biting and clawing himself helplessly...
Assuming Remus was still alive. He liked to think that he'd know if anything had happened to Remus... but as deep as an animal's connection with nature might be, it did not extend to sensing the death of a companion at great distances. Or perhaps if it did, it didn't work when they were in human form; he hadn't felt James' death.
A faint whine escaped his throat as he dropped his head back onto his paws. Something told him, deep down, that his friend was still out there, alone, and currently in terrible pain.
Moments later, it was a human Sirius Black who lay curled into himself in the dark corner of the cell, unable to see the sky or to feel that call. He couldn't remain transformed any longer. For a creature who lived by instinct, sensitive to the ebb and flow of nature, knowledge of the full moon made his imprisonment more terrible than the dementors ever had.