Albus made several brief visits over the remainder of the year, each time looking more tanned and wearing a set of robes more garish than before. He didn't leave behind any more luxuries but the dark wizard didn't need them. He had a goal now and that was to escape. He'd renewed his search into a weakness in the wards and wandless magic became an obsession.
It occurred to him one morning as he took a break to drink a cup of warm water on his window seat that he might have been going about escape entirely the wrong way. A muggle aircraft moaned far overhead as it crossed the sky and Gellert's brilliant mind was quick to form a surprisingly simple plan.
It was impossible to conceal his excitement from Albus at his next visit; there was an animation to his movements that he had been almost unable to disguise. Fortunately the tidbit of information that he'd withheld earlier could now be put into great effect. It had taken him less than a week to realize Albus' problem at Hogwarts was caused by a basilisk but he'd said nothing because the light wizard visited him far more often when he wasn't gainfully employed.
With this piece of information, the headmaster apparated away and Gellert was free to assume that he'd be left undisturbed for several weeks at least. Not that he intended to remain in Nurmengard for that long anyway.
He concentrated for a moment and cupped his hands, blowing into them gently. Blue light flared up suddenly and spilled from his hands to form a ball of flames on the floor. He smashed a hole in the coffee table and placed it over the fuelless flames, them his chamber pot took the form of a cauldron balanced on top. He filled it with water from the tap, then let it boil over the flames.
He pulled the chicken drumstick from where it had been stashed down the back of his chair after Albus' last visit. He stripped the flesh and dropped the bone into the pot, using a wooden splinter from the tabletop to stir anticlockwise twice. The potion hissed as he added a long strand of Albus' beard that had been stuck to the chair and turned a cloudy mauve. He began to recite an old incantation, dropping in a still living spider.
When the potion turned grey he paused and had to extinguish his cauldron stand that had begun to smolder. Then he reverently removed the stone from beneath his blankets and smashed it into the wall. A shard about the size of his thumb nail broke off. He repeated the action, then gathered the razor sharp stone pieces, clenching them in his fist even as they split the skin.
He repeated the incantation again, waving his free hand over the chamber pot as if he held a wand, then opened his other hand, dropping blood coated shards of philosopher's stone into the mixture. Steam exploded from the small pot with a sound like a train whistle and black flames licked across the surface. Gellert observed it with a grim smile before retrieving the delicate china cup and carefully pouring a measure of the potion out. He held it up to the window as if in a toast.
'To Albus Dumbledore; the wizard who fails to see the evil in us.' He purred before downing the cup. Without hesitation he plunged the cup back into the potion for another dose, downing it even as his face screwed up in pain. Black fire burned down his skin as he drank the third cup full and he was on his hands and knees to drink the fourth straight from the chamber pot having dropped the cup and smashed it.
He lost consciousness as the last drop passed his lips, consumed in a world of fire and ice.
He regained consciousness the following morning and wondered for a moment why he was on the floor. Then he noticed that the ever present pain in his knees had gone and sat up quickly, everything rushing back to him. His hands flew to his face, brushing against smooth unlined skin. He ran them over his scalp, disappointed to find that it was bald and hoping that his hair would grow back eventually. He stood up and stretched his pale, flawless limbs and embraced his magic. It flowed through him with more power than he had ever experienced; a combination of his strong youthful body and the discipline of old age. He looked for the first time around the cell, noticing the charred walls and furniture. The couch had been burned of all its padding and the chamber pot was a twisted hunk of metal.
The philosopher's stone alone remained untouched, although the two shards that he had broken off were massive scars in its otherwise perfect facets. His clothes had been burned to cinders but he could easily acquire new ones once he obtained his freedom.
As a last touch, Gellert picked up the charred coffee table and used it to scratch a message to Albus on the wall. Then looked out of the window and up at the muggle aircraft that always crossed the sky at midday. He pointed pristine finger up at it and spoke the incantation, he had to wait for a moment for the magic to make contact, then there was a brief resistance as he fought to overcome the engines. Abruptly the resistance stopped and Gellert saw smoke suddenly pluming out from behind the aircraft as it rocketed towards him.
He held the spell tensely as the mass of metal rocketed closer, then just before it hit the wards he released his magic and as expected the plane fell through without resistance. The ward's weren't tuned to stop non-magical items passing through. Of course, the alarms would have gone off in the ICW but the plane collided with the base of the tower and exploded in a plume of fire and smoke.
Simultaneously the wards fell, their shattering masked by the explosion of the plane. He'd hit his target perfectly, decimating the ward stone and bringing down Nurmengard's defenses with it.
The dark wizard didn't allow himself a moment to celebrate, taking off at a run to his old rooms. His original wand was still in his wardrobe and the emergency bag that he'd packed back in 1945. He allowed himself a savage grin as he grasped his wand and disapparated with a crack.