Disclaimer: All characters belong to J. K. Rowling.
A/N: I'll refrain from saying it throughout the rest of the story, but reviews are always very much appreciated!
It was early morning, yet dark as night – and far colder. Mist cloaked the island, sea mist that left water running in rivulets down the creases of rocks, to pool and turn to cracked ice at their bases. No matter that winter was long gone; on the island it was always deathly cold and shadowy, and as the five-foot thick walls of the prison let no murmur escape from within it was also as stiflingly silent as a grave.
So when the sudden noise shattered the air it was piercing enough to jolt the dead from their slumbers. It was a long, drawn-out wailing, it was a shrieking cry to the darkness, which seemed to cause even the strong enchantments wrapped round the stones of the fortress walls to tremble. It was the Azkaban prison siren, warning every hooded guard on the great rock of the escape of a prisoner; one miserable unfortunate whose body would surely soon hang limp and lifeless on the rocks, whose deathly blue lips would bear the imprint of the Kiss...
The mist seemed to shrink and beckon, waiting for the emergence of the escapee from the stone fortress. And it was not disappointed; within seconds, a thin dark form could be seen flinging itself forward with strength and speed, bounding with a strange grace and iron purpose over the rocks. But it was not a man. It was a dog.
The dog ran for its life, leaping over the salt-stinking rocks and slipping in the sea-slime. Its hollow eyes blazed in its wolfish face, burning with intent and some deep, unspeakable anger. Already the dark forms of the prison guards were rising gloatingly from the castle, the gaping hole of darkness in their hoods turning, searching...
But the dog did not look back. Its limbs were cramped and painful after twelve long years of confinement to a ten-foot cell, and its breath came in hot, agonising gasps. The strength with which it forced its thin legs to cover the ground, to claw its way over rocks, to swim for short stretches through sudden deep and freezing pools of salt-water came from some untapped resource, some rekindled fire. The great rock on which Azkaban was built was over two miles wide, but the sea was suddenly within sight and the mournful sigh of the breaking waves within earshot.
With the first taste of sea-spray, the dog also tasted freedom. It no longer felt the pain in its over-worked limbs, no longer felt fear for those hooded figures which were now, it knew, gliding with terrible speed over the rocks behind him – it feared nothing, because it was too close now to feel anything but exultation. When a dark-cloaked guard rose up seemingly out of nowhere, less than ten yards away, it was with a derisive bark and shake of the fur that the dog lengthened its strides, evaded the Dementor, forced its lean body between the bars of the great iron gates, and plunged headfirst into the sea and the enveloping mist.
The guards turned their hooded faces towards the sound of the splash, but it was too late. Confused impressions of some half-human presence had swum past their senses, and aimlessly they struggled to pinpoint the ever-retreating intelligence – then the dog forced its way further through the battering waves, nose lifted desperately above the rolling water and front paws paddling furiously – and it was gone.
And while the exhausted animal fought its way furiously through the battling waves, choking on salt water and freezing half to death in the cold of the North Sea, and slowly by slowly escaping the utter cold and darkness that hung perpetually round the island, an urgent message was being relayed through the Ministry of Magic that, for the first time in history, one of the highest-security prisoners had successfully fled the wizarding fortress of Azkaban.