A/N: Thank you for your kind reviews.
Chapter Three: Azkaban
When Harry arrived back at the Dursley's house that night, he was surprised to find that he had been given Dudley's second bedroom. They had apparently taken Ginny's threats to heart. However, their attitude toward him had not changed in the least. They ignored him and thankfully didn't notice that Harry now owned a lot of abnormal junk that they definitely would not approve of.
Along with Hedwig and her cage, he lugged the new trunk that Ginny had persuaded him to buy up to his new bedroom, opened it and began removing all the shopping bags and packages that he had acquired throughout the day. Ginny's advice had turned out to be dead useful when it came to making purchases.
She had advised him on what cauldrons to buy, pragmatically recommended that he purchase used rather than new History of Magic textbooks, and discouraged him from buying other things he definitely did not need. She had also assisted him in accumulating a rather large collection of Defense books, though she told him that they would be more useful as reference books until he had a broader understanding of magic in general.
All in all, the trip to Diagon Alley had been very enjoyable for Harry. Not only because of all the new discoveries he had made and things he had bought, but more because of Ginny's company. He found that he rather enjoyed being with her.
After he finished sorting his new possessions, he picked up one of the Defense books and sat on the bed. "The Light Overpowereth the Dark." he whispered, reading the title. This was one book that Ginny had specifically asked the clerk at the book shop for before they had even browsed the other available titles. The clerk had produced it from a locked cabinet behind the counter and it had cost Harry a pretty penny. Ginny swore that it would be worth it though.
Ginny had instructed him to study a certain spell in the book, telling him that it would be helpful with regard to her plans for breaking Sirius out of Azkaban. She also had told him that when he mastered the spell, she would explain the details of her intended prison raid.
Harry was very excited to hear that he had a godfather, a person his parents had known and loved. Consequently, he was very eager to help in anyway. With an exaggerated bout of enthusiasm, he decided to read the book's introduction, but his spirits were considerably dampened by the author's complicated theorizing about the Light and the Dark.
He decided to move on to the part Ginny had advised him to read. The Patronus Charm. The author went into great detail about the said charm, explaining both the theory and the practical use of it. Ginny had told Harry that she particularly appreciated this text for how the author so carefully explained the wand movements associated with the each spell and had then explained to Harry that the thoughts and wand movements behind each spell were much more important than the words used.
Realizing that he should probably practice, Harry eagerly grabbed his new wand and careful not to actually cast the spell, began to practice the movements for the Patronus Charm. He did this exercise sporadically over the next few days between chores and other things. He loved imagining himself in various duels with Dark wizards. A side effect of all this imagining was the increase of Harry's ability to put emotion behind his spells.
When Ginny Apparated into his room late one evening, he was in the midst of one such practice. "Impressive." Ginny said by way of greeting.
Harry jumped sheepishly and turned around to see her. "You said the wand movements were important so I was practicing."
"You were doing very well." Ginny assured him. "I think you have the basic movement down." She produced her Cherry wood wand and used it to place privacy charms and spells around the bedroom. Another more complicated spell enlarged the room considerably. "Let's see you do it again, except this time- use my wand and say the incantation. Remember to think a happy thought."
Taking the proffered wand from her hand, Harry put his own on his bedside table and then turned toward the enlarged room. He shifted into the appropriate stance and paused, feeling extremely awkward and self-conscious now that he had an audience.
Harry glanced over his shoulder and caught a glimpse of Ginny. She was watching him soberly with patience and encouragement in her eyes. "Go on," she urged.
She warmed his heart and he realized that he did not need to feel awkward or self-conscious in front of her. It was this emotion he did not quite understand that overwhelmed him as with sharp textbook precision he cast the charm. "Expecto Patronum!"
A silvery mist hissed forth from the wand and lingered for a few moments before fading away. "I don't think I got it." Harry sighed.
Ginny shook her head. "No. But you came very close."
"What did I do wrong?" Harry asked.
A sigh escaped from Ginny's lips. "It's not that you did anything wrong, Harry. You just need more experience and foundation. You did very well for your first time."
That was an understatement, Ginny admitted to herself. Trying to teach him the Patronus Charm before he even learned any other significant spell was insane. Most witches and wizards who had left Hogwarts had difficulty with this spell. She was trying to teach it to him before he even stepped foot into Hogwarts.
Ginny didn't want to leave him out in the cold with regards to breaking Sirius out of Azkaban, but she didn't want to let him step foot near Azkaban without being well-prepared to defend himself either.
In the days between their visit to Diagon Alley and now, Ginny had debated with herself over whether it would even be possible for him to succeed. He's too young, one voice had argued in her head. You're expecting too much from him. Another more logical voice had pointed out that Harry was powerful and would already have enough strength to cast the Patronus Charm. Another voice reminded her that it would do no good to imagine up limits and barriers that weren't necessarily there and that it would be best to simply keep trying.
"But?"
This jerked Ginny out of her thoughts. "But what?"
"You said I did well for my first time." Harry reminded her. "But what did I not do right?"
"No, you did well, really." Ginny said. "It's a spell that takes a lot of practice before you get it right. It's like a bicycle. Once you get it, there will be no problem."
Harry tried again and got the same result. "Surely there is something more I can do."
"You're focusing on a happy thought, right?"
"Yes." Harry affirmed.
"Good. There's a couple of things you might try." Ginny said, approaching Harry. "I've found they help me enhance my own spell casting ability." She took his hand and shifted it slightly, angling the wand a tad. "Do that and then don't grip your wand so hard. Let it loose a bit. Now do the wand movement, but try to make it more smooth and fluid. Try again."
This try produced a more substantial silvery mist, much to Harry's delight. He was improving!
"Now," Ginny lectured, "this is primarily an offensive spell used against Dementors in which you attempt to overpower them. They are Dark creatures that guard Azkaban." She then briefly explained these creatures and her knowledge of Harry's particular vulnerability to them. "With other spells you cast them and maybe they hit the target and then they do their job. With this, you might have to maintain it a bit if there are a large amount of Dementors who don't flee at the first sight of your Patronus. Pretending that you're maintaining it in such a way might help you get better results. Here's how you can do that."
She picked up Harry's wand from the bedside table and used it to demonstrate. "You do what I have taught you, the smooth movement, then you cast it. Don't cut loose from the result though."
Ginny did the movement that Harry had come to recognize and then instead of moving the wand or shifting it after the spell would have been cast, she held the wand in place, pointing it at where a Dementor might be. "I would want to keep focusing on my happy thought and on putting energy in the spell. I would also want to brace myself like this." She moved her right hand back a little bit and shifted her stance slightly. "Did you get that?"
Harry nodded and now knowing that he was especially vulnerable to Dementors fiercely resolved to put his all into his next attempt. He did just that as he mimicked Ginny's every movement during the demonstration.
The silvery mist that hissed from his wand was impressive, without a doubt. Though it failed to form Harry's stag, Ginny was nevertheless pleased. If it was not an example of a Patronus, it was certainly an example of Harry's power. He would do very well when he got to Hogwarts if he capitalized on the basic principles she had taught him in an effort to help him succeed at the Patronus Charm.
She spontaneously praised Harry for his effort, instantly wiping the look of disappointment off his face. "Well done Harry!"
They decided to call it quits for the night but agreed to meet the next night and every night thereafter until he was able to master the spell. They did so and Harry's Patronus gradually improved as August wore on. Ginny was thrilled with the progress that they were making, but Harry was becoming despondent, fearing that every spell he ever learned would be as difficult.
This all came to a head one night after another one of Harry's failed attempts to produce a corpeal Patronus. He sat down on the bed. "It just isn't happening." he sighed.
Ginny felt terrible. She had pressed him to learn this hard spell and he was being defeated by it. He had trusted her to guide him and now it seemed as if she had been battering him against a brick wall for nothing. "I'm sorry, Harry." Ginny apologized as she joined Harry on the bed and without thinking, wrapped her arm around him comfortingly. "Perhaps I'm expecting too much."
"No." Harry rushed to reassure her. "It's not that, exactly. I think I should be able to do it, it's just that I can't see myself doing it."
An idea jolted through her head. The Harry of the future had faced the same problem, until he saw himself cast the Patronus to save his and Sirius' life in his third year at Hogwarts. She could use the Pensieve and show Harry himself casting a Patronus!
"I think I know what we need to do." Ginny announced. She got her wand from Harry. "I'll be back in a few moments."
It wasn't very long before she returned, holding a curious looking bowl full of a strange liquid. "This is a Pensieve." she explained to Harry. "I brought it from the future with me. It contains a lot of your memories. We can watch you cast a Patronus."
Harry stared at the bowl and the memories swirling within. For some reason, he felt a very strong revulsion to it. He did not want to be connected to his old self's memories.. "I don't know about this." Harry said, backing away from the bowl Ginny was holding. "I don't really want to see my own memories."
Ginny was confused. "Why not?"
He shuddered. "I don't know."
"It's all right." Ginny said thinking quickly, reckoning that it would be easier to come up with another solution rather than try to convince Harry otherwise. "I can put one of my memories of you producing a Patronus and we can watch it instead."
This seemed to be an acceptable compromise for Harry, though he still felt uneasy. He watched as Ginny put her wand to her head and withdrew some of the same substance that was floating in the bowl. She mixed it in and then held out her hand for Harry.
As soon as he grabbed her hand, they found themselves on the main street of some village. Harry watched as two people- his older self and a different Ginny walked down the street, keeping to the shadows.
Harry felt a sudden feeling of gloom descend and before he could ask the Ginny he came with about this, the other Ginny yelled. "Dementors!"
He watched the events unfold. He watched as his alternate self cast the Patronus Charm. In awe he watched as a stag exploded from the wand. The stag effectively drove away the Dementors and then he blinked and found himself back in his bedroom at Privet Drive.
Ginny was watching him carefully. "Would you like to try one more time?"
"I suppose so." Harry said, feeling more confident now.
Ginny returned the wand to him and he prepared to try again. Before he could do that, he was interrupted. "Wait!"
"What?"
"I was just thinking that we might try somewhere else with more room." Ginny told him. She grabbed the wand back and used it to Apparate them to the top of a small hill in a moonlit clearing.
"Where are we?" Harry demanded.
"In the middle of nowhere." Ginny said as she handed him back her wand. "Now try."
Harry's daydreams came into play as he imagined that he was in a fight for his life against the deadly Dementors. He brandished Ginny's wand and waved it, shouting the necessary incantation, pouring his happiest memories and willpower into the spell.
He was well rewarded as a larger than life stag exploded from the wand and charged the horizon, pulsating as it lit the countryside for miles. After a while, it disappeared.
Harry was quite pleased with himself, but Ginny was beside herself. "Amazing Harry! Truly amazing! I can't believe it!"
"Amazing?" Harry asked. "I was beginning to feel pathetic. Surely a better wizard would have been able to learn that spell faster. If it takes me that much effort to learn every spell, I'm going to be in trouble!"
Ginny laughed. "You just cast a spell that most adult wizards and witches can't. They don't even teach that spell at Hogwarts normally. I promise you that most spells you learn will be easier than that one, Harry."
"Are you serious?" Harry wondered.
A demonstration seemed in order. Ginny motioned for her wand and then used it to cast a stunner. "Stupefy!"
Harry watched the red beam of light jump from the wand curiously.
"Now you try."
He took the wand, carefully imitated her every moment and shouted, "Stupefy!" A red beam of light shot from the wand. "Wow!" he exclaimed.
Ginny smiled at him. "Most spells will be much easier for you now. Your struggle at Hogwarts will be with magical theory and other subjects that have less to do with wands, I expect."
Harry remembered her promise about Sirius and Azkaban. "Do I get to hear your plans for breaking Sirius out of Azkaban now?"
"Of course." Ginny said. "Let's return to your bedroom, though."
Upon their return, Ginny conjured a chalk board and some chalk and proceeded to draw a diagram of Azkaban and the shoreline near the dread island while explaining what defenses were in place and where they were located.
"There are Aurors stationed at the dock with the boats." Ginny told Harry. "I'm afraid that the only way we can get to Azkaban is via the boats. I can overpower and take the Aurors out of commission easily, especially because we'll have the element of surprise on our side. Once we get a boat though, the next step is yours."
"What do I do?" Harry asked, feeling like he didn't really have much to offer.
"The Patronus, Harry! I do believe your Patronus is strong enough to overpower any Dementors that notice us and will be attempting to prevent our reaching the island. Once we're on the island, it will be strong enough to keep the Dementors away while we attend to business."
Harry felt a little foolish for not realizing that. "Er, right. Wouldn't you be better at taking care of the Dementors? You're more experienced."
"No, you're better Harry. Your Patronus is much more stronger than mine. That's why I never actually showed you my Patronus to demonstrate when I was teaching you. I didn't want you to get any limits or pre-conceived notions in your head." Ginny said, both answering his question and explaining her past actions.
Ginny went on to explain the rest of her plans and filled Harry in on the little necessary details. He asked plenty of questions, trying to make sense of all of the information. By the time Ginny left, he was confident that he could handle his part in the raid which was set to go down on the night of 30 August.
Mrs. Weasley waited until 30 August to take her children to Diagon Alley so that her sons who would be attending Hogwarts that year could obtain their supplies. Ginny had been unable to escape Mrs. Weasley's demand that she come with them.
As they walked past the wand shop, Ginny felt an immense amount of relief that Ron would not be getting a brand new wand year. Mr. Ollivander would have been difficult to deal with. The trip was uneventful, excepting a few disturbances that may or may not have been caused by the twins, but it was long.
This resulted in it being rather late once they returned to the Burrow. There was no way for Ginny to duck out of helping cook, serve, eat and clean up after dinner. Consequently, she was quite late when she Apparated into Harry's bedroom.
"What happened?" Harry asked, worry etched into his young face.
"Nothing." Ginny muttered. "I'm just a little behind schedule. There's nothing to worry about. Where's your bathroom?"
Harry pointed. "That way, down the hall- be careful of the Dursleys though."
"Worry about them, not me." Ginny quipped. She hefted the knapsack she had brought along with her and exited the room, quickly finding the bathroom.
In the knapsack were some old clothes and other things she had appropriated from the Burrow. No one would notice their absence, and later- complete destruction. Ginny changed into these clothes and then with the aid of the mirror began magically altering her appearance.
She had put a lot of thought into this particular disguise. It was a disguise that she wanted anyone who might see her to remember. Her hair became quite shorter and changed from red to blonde. She changed her eyes to the brightest shade of blue possible. Other parts of her body were also significantly altered, as well as her height.
Further magical precautions were taken. A spell to prevent the loss of even a single hair from her head or body was cast. She didn't need the Department of Magical Law Enforcement to find one of her hairs and put it in a Polyjuice potion. Another spell disguised her aura, another her voice, and so forth.
At last, Ginny strapped on two wand holsters that must have been a hundred years old. The knapsack had one last object in it. It was the goblin-made wand. Ginny withdrew it and held it up, studying it closely. The veins of light crystal glowed brightly while the dark crystal glowed with an eerie light as faint traces of Fiednfyre swirled in its depths. The black platinum shone brightly as well. It seemed to be greedily absorbing the light in the room while at the same time, shunning the light. Ginny had decided to bring it, just in case they ran into too much trouble. She gingerly inserted it into one of her wand holsters.
When Ginny returned to the room, Harry showed little surprise at her disguise this time around and stood patiently while Ginny made changes to him. He became a little taller and his hair lightened a little. His eyes became a very dull shade of brown and his face changed into something so boring, that no one would likely be able to remember it, even if they tried.
Ginny added the spells to prevent the detection of his identity and then one last spell to make him invisible to all but herself. They had planned to make him invisible from the start, but Ginny had opted to also disguise him in case he had to reveal himself, whether it be by accident or design.
They quickly reviewed the steps of the plan and without further ado, Disapparated to a certain place near Azkaban. It was beyond the security wards, so their arrival went undetected. The blokes at the Ministry hadn't seen a war for a while. Therefore, their defenses, planned from a dreary desk, had failed to account for potential attackers approaching the guard station and boat dock on foot. Consequently, Harry and Ginny approached the guard station and crouched below one of the fortified windows without being noticed by the guards within.
They could hear only silence. Suddenly an explosion sounded and both Harry and Ginny jumped with fright. This is it, Harry panicked, we've been discovered and we're about to die! Nothing happened though.
Cursing was heard from within the station and one voice challenged the cursing voice to "another round."
Ginny let out a sigh. "They're playing Exploding Snap," she explained to Harry. "It's a magical game."
Harry thought it was ridiculous. Who wanted to play a game that exploded? Cursed Aurors.
"Are you going to attack them yet?" Harry asked Ginny.
"No." she muttered in a low voice. "I can only account for three. I think there's supposed to be four."
"What do we do?"
"Wait." Ginny replied. "We need to figure whether there's a fourth guard and if there is, where he is."
It was nearly an hour before Ginny decided that it was safe to assume that the three Aurors playing Exploding Snap were the only Aurors. After that it was short work to deal with them. "Wait here." Ginny told Harry.
Ginny stood up, walked around the building, and blasted open the door. The Aurors stared at the black robed and blond witch with surprised expressions on their faces. Two were stunned before they even considered drawing their wands. The third had drawn his wand and erected a shield, but there was simply too much force behind Ginny's stunner. Ropes flew from Ginny's wand and tied the downed Aurors and Ginny retrieved their wands. She placed them across the room, well beyond their reach should they regain consciousness before she and Harry finished their job.
Harry had watched from the window, being invisible. "Wow!" he exclaimed. "You're really good."
"It's more that they were too complacent." Ginny told him. "The element of surprise is very important in a fight. As one of my favorite Aurors would say, constant vigilance!"
They proceeded down to the dock and commandeered a boat. With a quick tap of Ginny's wand, it started moving of its own accord toward the dread fortress of Azkaban that loomed ahead of them.
The boat had not carried them far before they were suddenly surrounded by a deluge of black-robed figures floating and flying through the air. "Dementors!" Ginny hissed. She shoved her wand to Harry. "Hurry! Cast the Patronus Charm."
Depression was grasping Harry already. He began shaking as Ginny handed him the wand. Desperately, he tried to think of happy thoughts. He found his happy thoughts and managed to gasp out the incantation, waving the wand at the Dementors.
The stag exploded from his wand and began running around the boat in circles as it moved through the water, effectively causing the Dementors to retreat. The Dementors disappeared and the stag took position ahead of the boat, riding on the water, leading them to the island's dock.
"Someone has sounded the alarm." Ginny stated in a matter-of-fact voice. "Otherwise, the Dementors would not have been privy to our presence so quickly. We must move fast. The Ministry Aurors will be on their way shortly."
"Who would have sounded the alarm?" Harry asked desperately.
"The fourth Auror." Ginny answered grimly. "I should have guessed. He or she must be on the island."
The boat continued toward the island with Prongs in the lead and stopped at the dock. Ginny reclaimed her wand from Harry and instructed him to stay out of the line of fire. She then approached the entrance to the prison with Harry cautiously following. Prongs was still present, but was out of sight.
The fourth guard turned out to be a he. He was standing in front of the gates that led into the prison with a grim look on his aged and seasoned face. "Stop now or I will be forced to attack you!" he shouted at her. His wand was drawn and he was ready to do battle.
Ginny did not stop and the Auror fired a rapid volley of spells at her. A swish of her wand produced a magical barrier that absorbed all the spells. She released the barrier and before the Auror could fire another spell, she disappeared into a cloud of bright yellow smoke that had abruptly swirled into existence around her.
The Auror was not distracted by the smoke or unnatural color of it and instantly realized that she was trying to fool him. Assuming that she was trying to get behind him, he whirled around to where she might appear.
Ginny had taken into account his experience and the likelihood of him guessing what she might do under cover of the smoke and was well prepared for his reaction. The smoke dissipated as the Auror whirled to reveal Ginny standing in the same place. The Auror fell after being stunned in the back.
Harry rushed up as soon as the Auror fell. "Is he all right?"
"Yes." Ginny answered as she used her wand to create a Portkey. She put it in the stunned Auror's hands and it activated, carrying him away to a safe place. "Let's get moving. Call your Patronus."
Harry caught sight of the stag, still prancing around and summoned it. "Hey! Follow us." He commanded, feeling a little silly for talking to something that wasn't a human. The stag came to them and began following them closely.
They entered the prison and were pleased to find a prisoner roster and map of the prison on a bulletin board right near the entrance. It seemed the prisoners were arranged in the prison according to their supposed crimes. Sirius Black for some odd reason had been placed on the top floor. Alone.
This annoyed Harry to no end for several reasons, but Ginny was pleased, saying that it was convenient for them. Without wasting another moment they rushed to the lift, but were unable to activate it. Ginny cursed, surprising Harry with her language. With her wand she destroyed the mechanism that operated the lift explaining to Harry that if they couldn't use the lift, then the backup Aurors weren't going to be using it either. They found the stairs and charged up.
They encountered a horde of Dementors at the first level up, but the Dementors fled at Harry's Patronus. The same occurred at every level of the prison, though with each level they ascended, there seemed to be less and less Dementors.
It seemed as if the top would never come, but after brief rest stops and a lot of heavy breathing, they made it there. There wasn't a single Dementor on this floor, nor had there been any on the two floors beneath. Ginny explained that there probably weren't any prisoners on those floors and one prisoner was hardly worth a Dementors continued presence on this top floor.
The lack of Dementors caused Harry's Patronus to fade away. This left Harry and Ginny to search the floor alone, being able to feel the subdued gloom from nearby Dementors. Each cell was locked and chained shut despite their being empty. Or so Harry thought. A wave of Ginny's wand and the resulting explosion revealed the inside of one cell. There were the bones of some unfortunate prisoner.
"I'm guessing they haven't used this level of the prison for a few centuries." Ginny told Harry. "They properly take care of the bodies of those who die now. The Ministry must have had a lot of anger toward Sirius to put him in a part of the prison so old and dreaded."
They continued down the hallways, blasting open various cells as quickly as possible. Most cells had human skeletons, but some had goblin skeletons. Ginny had felt angry heat emanate from the goblin-made wand at each of these discoveries. She didn't stop to think of the repercussions that these unfortunate discoveries might cause.
Another cell door was blown from its hinges and at long last they found him. Sirius Black was huddled in the corner and staring at them with mixed emotions on his face. He'd probably heard the explosions coming down the hall toward him.
"Padfoot, we're here to set you free." Ginny announced. "We know you're innocent."
"Who are you?" Sirius managed to say weakly. "And who is we? I see only one of you."
She waved her wand and Harry appeared. A few uttered counter-spells later, Harry Potter stood revealed. "This is Harry Potter."
Sirius gaped at Harry, the expression on his face betraying that he recognized Harry's looks and the scar on his forehead. "How dare you bring him to this dangerous place, whoever you are!" he declared vehemently.
"Oh please." Ginny muttered, her face heating up behind the illusion spells. He was right, kind of. "I needed him to get past the Dementors. Hurry, we've got to get going. The Aurors are on the way."
Sirius stared at her with surprise in his eyes. Without answering he leapt from his sitting position and standing on his tip-toes peered out the cell window. "From the lights and movement I can see down at the dock, I'd say they're here and possibly in the prison. What were you planning to do to get out of here?"
"I thought we'd walk out and use a Portkey," Ginny explained. "I wasn't expecting you to be on the top floor and I wasn't expecting the Aurors to show up."
"We need to think of something." Sirius muttered, sinking to the floor because he was too weak to continue standing. "Apparition and Portkey's are no good inside the prison."
Ginny smiled triumphantly. She had the perfect backup plan. Before she could explain it or put it into action, a rushing cold enveloped them.
"The Dementors are coming." Sirius gasped. "A lot of them!"
"Harry!" Ginny cried urgently. "Your Patronus."
Harry took the wand and cast his Patronus. The familiar stag charged down the hall as Sirius gasped. He knew that stag. The Dementors appeared and instead of fleeing from the Patronus, they kept charging it until they met. Harry was prepared for this and was pointing his wand still and holding the spell like Ginny had taught him. The Patronus and Dementors were forced to stop as they pressed against each other. It was a stalemate. Neither the Patronus or the Dementors were moving now. "What's wrong?" Harry asked desperately, working to hold the spell.
Ginny seemed just as confused, but Sirius was cagier and could see what was going on. "The Aurors are driving them up here. The Dementors can't go back, but they can't go forward either."
"It's of no matter." Ginny declared.
Harry and Sirius turned to look at her. She was holding the goblin made wand. Neither of them had ever seen anything like it. Before they could ask about it, she commanded them to hold onto her. They did so while Harry continued to hold his Patronus Charm against the onslaught of Dementors.
She then waved the wand and shouted a long incantation. Streaks of fire and lightning leapt from the tip of the wand and rushed out the door of the cell and spread through the corridors, multiplying. Though Ginny did not realize it, it also spread to the two floors beneath them. Ginny then screamed very loudly. "Fides!"
The phoenix appeared much more quickly than Ginny had expected and whisked them away from Azkaban in a puff of flame. What happened next revealed how fortunate Fides' timing had been.
Ginny's intent in casting the spell was only to destroy the nearby corridors to prevent the Dementors and Aurors from reaching them while they waited for Fides and made their escape. Ginny had not realized that the goblin-made wand had become much more powerful since Ginny had actually used it last. In addition, the goblin skeletons had aggravated the wand.
The Aurors in the prison who were rushing to the top floor could only hear the explosion and feel Azkaban's foundation shake, but the Aurors outside watched with terror in their eyes as the top three stories of the prison were annihilated.