They kept on running, Ron limping slightly thanks to a twisted ankle, only stopping to duel. It was only now that they seemed to fully appreciate the scale of the castle grounds. Skirting the lake, they aimed to approach the main battle from behind until, shockingly simultaneously, they all fell flat.
"Trip jinx, Potter." A voice drawled from behind a bush. Malfoy, Crabbe and Goyle stepped out. "Thought you'd have learnt."
"Tarantallegra!" Hermione shouted swiftly, hitting Malfoy squarely in the chest. Malfoy's legs immediately went into an uncontrollable quickstep.
"STUPEFY!" Harry and Ron cried simultaneously, sending Crabbe and Goyle flying. Malfoy, by now, had managed to utter the counter curse and had already levelled his wand at the four of them.
"Cruci-."
"PROTEGO!" Kathryn cried, managing to deflect the curse just in time. "Dear me Malfoy," she shook her head, "using unforgiveables. That will land you in Azkaban if you're not careful." Her voice was caustic.
"Avada Kedavra." Malfoy spat. They reacted too slowly. Kathryn was knocked off her feet by a blast of green light.
"NO!" Harry and Hermione cried.
"I'm fine." To their amazement she stood up, sporting no more than a bloody nose. "He's not got the backbone for that kind of stuff." She commented scathingly, wiping the blood dripping from her nose with her sleeve.
"Yes I do!" Malfoy screamed. "Crucio!" this curse hit both Harry and Kathryn; sending them falling to the floor in pain, their scars burning on their foreheads. "Not so tough now are you?" he laughed coldly.
"Petrificus Totalus!" Ron shouted angrily, the spell missing Malfoy but distracting him enough to stop the Cruciatus curse that he was using on Harry and Kathryn. Their scars stopped burning and they lay on the grass, panting for breath.
"EXPELLIARMUS!" Kathryn and Harry yelled at the same time, sending his wand flying out of his hand. Grabbing the flying piece of wood, Kathryn tucked it into one of her cloak pockets.
"Petrificus Totalus!" Ron followed, hitting him with a jet of red light. "You are absolutely pathetic!" Ron shouted at Malfoy, giving him a sharp kick in the ribs. "You're bloody lucky we're in good moods otherwise we'd be killing you instead of sending you to the Dementors.
"Ron, come on." Hermione tugged on his sleeve. Ron, scowling, gave Malfoy one final kick before following the rest of them.
All of a sudden, the sounds of battle deadened a silence only Dementors could bring was sweeping through the night; engulfing them like fog. Swirling figures of pure darkness appeared all around, moving in a ghastly procession towards the castle; their faces hooded and their breath rattling. Cold, sharper than broken glass, permeated what would have been a pleasant summer's night.
"Come on," Hermione whispered behind them, "Patronuses, come on!" Harry and Kathryn raised their wands but an acute hopelessness filled them; how many lay dead around them, how many had sacrificed themselves?
"COME ON!" Hermione screamed.
A hundred Dementors were advancing, following the scent of Harry and Kathryn's despair like an animal sniffing out fresh meat. Ron's terrier and Hermione's otter both burst into the air but flickered feebly and died. All Harry and Kathryn could do was stand with their wands trembling in their hands.
"Think of something happy." Hermione pleaded.
"Happy?" Harry's voice cracked.
"We're still here, we're still fighting." She whispered. "Come on!"
There were silver sparks in the oppressive blackness, then a wavering light, and then, with almost exhausting effort, a charging silver stag and a wolf burst from the ends of Harry and Kathryn's wands. Dashing forwards, they made the Dementors scatter wildly and the sounds of the battle reached their ears once more, the fresh night air refreshing on their faces as they took deep, steadying breaths.
They did not have time to speak as, with a roar and an earth-quaking tremor, a giant blundered out of the darkness.
"RUN!" Harry yelled, and they scattered as a gigantic foot landed exactly where they had been standing.
"Get out of range!" Ron yelled as the giant swung its club dangerously close, its cries of rage carrying across the grounds to where flashes of red and green light continued to illuminate the darkness like fireworks.
"The Whomping Willow!" Hermione yelled. "Go!" levitating a twig with her wand, she sent it zooming towards the knot that paralysed the branches. At once the tree went still and, before thinking about what they knew lay at the end of the passage, they dived in.
They knew Voldemort lay at the end of the tunnel, one of the binding flashes of pain that shot through their scars had shown them his hiding place. He wanted them to come to him and they needed to get to him to kill the snake. There were no other options left. They wriggled forwards through the narrow passage on their hands and knees, led by the narrow beam of light that Harry had coming from the end of his wand.
"Put the cloaks on!" Hermione hissed. They readily obeyed, throwing on the silky material. Extinguishing the wand, they moved forwards again, continually expecting to be discovered and to see a flash of green light.
Leaving Ron and Hermione back in the passage, Harry and Kathryn continued on into the Shrieking Shack, listening to the voices coming from the room directly in front of them.
"My Lord," it was Snape, "let me find them. Let me bring you the Potters, I know I can find them." Peering through a crack, they could see Nagini floating in the air, twisting and coiling, encased in a protective, shining bubble. Voldemort's pallor seemed to radiate through the darkness as he stood and paced the room.
"They will come to me Severus." He did not seem concerned that they had not appeared. "Do you know why I have summoned you from battle?"
"No, my Lord, but I beg you let me return. Let me find the Potter brats." They had never seen their normally demanding teacher so supplicant.
"You do not understand them as I do. They do not need finding; they will come willingly to me. They will hate seeing others struck down around them, knowing that they are the cause. They will want to stop it at any cost; that is their flaw. They will come."
"But my Lord, they might be killed accidentally."
"My instructions to my Death Eaters have been perfectly clear, Severus. Capture the Potters, kill their friends by all means, but leave them unharmed." Had this been any other situation, Kathryn would have pointed out that Draco Malfoy hasn't seemed to care as he's tried his luck with the killing curse.
"I can bring them to you, my Lord, they trust me, think me their ally." Snape pleaded; a tone of voice that they had never heard him use.
"You have been a good servant, Severus, but I grow tired of your duplicity." Voldemort paced the room, the swish of his robes sounding like the slither of a snake. Snape's face was like a death mask; marble white and it was hard to believe that someone still lived behind those black eyes. "I highly doubt that the man that pleaded with me to spare the life of a Mudblood will be so eager to bring me her children; the children who have constantly thwarted me." Snape did not speak; he seemed to have accepted whatever was coming. "I'm sorry it had to come to this."
"My Lord." Snape protested as Voldemort swished his wand through the air. Nothing happened, the killing blow did not fall, but then the true nature of the spell became clear. The snake's cage was rolling through the air and, before Snape could do anything, it had encased him.
"Kill." The command, spoken in Parseltongue, was incomprehensible to Snape but comprehension swiftly appeared in his dark eyes.
There was a terrible scream. The little remaining colour drained from Snape's face, his eyes widening in horror as the great snake's fangs slipped easily into the exposed flesh of his neck.
"I regret it." said Voldemort coldly. There was no sadness in him, no remorse. It was time to leave the shack and take charge. He pointed his wand at the cage that encased Nagini and it drifted up off Snape to hover in the air once more. Blood gushed from Snape's wounds but Voldemort paid it no heed as he swept from the room, Nagini floating along behind him.
Harry could hear Kathryn's frightened, rapid breathing from beside him as they waited for Voldemort to be completely gone. Once it seemed safe, she burst from beneath her cloak and dashed into the room as quietly as she could, towards the broken man lying in a pool of his blood. She fell to her knees beside him, not caring for the viscous red liquid that soaked through her jeans. Harry, Ron and Hermione followed, bewildered, as she moved his hand that had been trying to staunch the blood flow and began to run her wand over the deep puncture wounds in his neck, muttering under her breath. A terrible rasping, gurgling noise echoed around the empty room.
"Take…it…Take…it…" something more than blood was leaking from Snape. Silvery blue, neither gas nor liquid, it gushed from his mouth and his ears and his eyes. Harry knew what it was, having seen it many times before, but didn't know what to do. Hermione stepped forwards with a small vial and scooped the silvery element into it with her wand.
"Oh no you don't," Kathryn murmured as Snape grew paler still, fishing around in the concealed pockets in her cloak, throwing Malfoy's wand aside as she did so, "you're not ending like this." They watched, astonished, as she poured a generous amount of Dittany on the wound. She never took her gaze off his, hoping to keep him conscious for as long as possible.
"Lily…" he whispered so that only she could hear. "Lily…" Eventually, the blood flow stopped, but Snape had already succumbed to unconsciousness. He was still breathing, however, and Kathryn began to drag him towards the hidden passage.
"Come on, back to the castle." She grunted. "Locomotor mortis." She whispered, Snape's body hovering off the ground and following her as she crawled.
As they emerged back into the grounds, the battle appeared to have stopped. It was then that a high, cold voice rent the air, making them jump, thinking that Voldemort was behind them.
"You have fought," said the voice, "valiantly. Lord Voldemort knows how to value bravery. Yet you have sustained heavy losses. If you continue to resist me you will die, one by one. I do not wish this to happen. Every drop of magical blood spilled is a loss and a waste." There was a pause in which not a sound flitted across the grounds. "Lord Voldemort is merciful. I command my forces to retreat immediately and I give you one hour to dispose of your dead with dignity and to treat your injured." They didn't want to think of how many there could be dead.
"I speak now, Harry and Kathryn Potter, directly to you. You have permitted your friends to die for you rather than face me yourselves. I shall wait for one hour in the Forbidden Forest. If, at the end of that hour, you have not come to me, if you have not given yourselves up, then battle recommences. This time I shall enter the fray myself and I shall punish every last man, woman and child who tries to conceal you from me. One hour." The voice was gone as abruptly as it came.
"Don't even think about it." Hermione said sternly, seeing the looks on their faces. "We need to get back to the castle."
The ability to move rediscovered; they hurried up to the castle with Snape floating along beside them.
"Where is everyone?" Hermione whispered as they stepped into the Entrance Hall. The castle was oddly quiet, no flashes of light illuminating everything. Rubies and emeralds still littered the floor, which was heavily bloodstained, along with pieces of rubble from where the stairs had been hit whilst they were on them. Ron led the way into the Great Hall where the survivors had gathered.
The house tables had been pushed aside and the survivors stood in groups, some supported by others, whilst the dead lay in the middle of the hall. Madam Pomfrey was treating the injured up on the raised platform where the teachers usually sat. Kathryn saw Firenze amongst the injured, his flank pouring with blood, as she ran towards the dais with Snape. Leaving him in the hands of Madam Pomfrey, she rushed back to Harry who was holding the little bottle with Snape's memories.
"Let's see what he wanted us to." Leaving Ron and Hermione with the Weasleys who were huddled together, thankfully all still alive, they ran through the deserted castle, not stopping for breath until they reached the stone gargoyle that guarded Dumbledore's office.
"Password."
"Sugar Quill." They both said, dashing up the stairs as soon as they were visible.
Dumbledore's office was still, all of the portraits empty, their occupants probably trying to see what was going on in the castle. The stone pensieve lay in the cabinet where it had always been and Harry poured the memories into it, eager and anxious to see what they contained. Without hesitating, they grasped each others hands and dived headfirst into the swirling sea of memories.