Chapter Text
Ten days after Dumbledore's funeral, the wizard's spells faded from the world.
At Hogwarts, Minerva McGonagall stood rigid in the Headmaster's office, trapped in a web of light and magic as the castle searched for its new Mistress. Three hours after the magic had begun to infuse her spirit, to build new wards and transfer rights and privileges, it gently sat the trembling witch on a deep cushioned chair, House Elves appearing with tea and strengthening potions to minister to her.
When she was able to raise tear-filled eyes, she spoke to the sleeping portrait behind her desk. "What have you done, Albus?" she whispered. Trembling, she rose to face him, shoulders back and head high. "Even dead you want to control us, to lead the battle, to keep us all in our places on your chessboard, convinced that there was no better mind, no more complete strategist than yourself." The tears in her eyes dried in the heat of her anger. "All of us, all of us friends," she ground the word out between her teeth, "all of us colleagues, powerful witches and wizards, good and decent men and women who fought and bled and died under your orders could never measure up to your standards of wisdom. We could not be trusted to contribute in some educated fashion. You convinced yourself that we had absolutely nothing to add to your genius."
She turned her back. "I have wasted enough time – far too much in considering what the great Albus Dumbledore would want me to do." She raised her arms and drew complex runes, murmuring long phrases, undoing charms, breaking wards, and building newer, thicker ones. "I may not be Albus Dumbledore," she murmured, jamming her wand into the air to punctuate the new order she'd put into place around the castle, "but I am Headmistress of Hogwarts. And I will protect our children – all of them – until there is no breath left in my body."
A flare of heat under her breast concentrated her focus. Alarms – immediate alarms shook her. As soon as her new wards took hold, Hogwarts raised alarms, pinpointed deadly, dark spells or artifacts inside the castle. In Hogwarts. A school for children. "Never," Minerva whispered. "Hogwarts," she announced, feeling the command reverberate from the stones beneath her feet, "watch and ward."
In the air before her, a map of the castle appeared in glowing lines of green and yellow. Dark blots emerged, revealing the locations of the threats. Deep beneath the first floor washroom she recognized the Chamber of Secrets. She nodded. She, Albus, and Severus had explored its reaches thoroughly after Harry's second year. Her gaze moved to the Slytherin Common Room. Several curses had lodged there, cast either by unknowing students or perhaps Tom Riddle himself during his years as a student here. With an unvoiced command, Hogwarts destroyed the lingering magic, commanded to cleanse and purify the Common Room as well as the student dormitories.
Severus' quarters revealed a pattern of darkness. His Dark Mark left its traces, even after the murderer had fled. Minerva allowed her rage to fuel her magic, diving deeper into Hogwarts, tracing connections, images, any darkness remaining within the traitor's secretive lair. Other items glowed - various potions ingredients. Severus had set his own wards to keep their effects trapped. She would leave those for the moment. His Floo had been shut down, the secret exit he had installed laid with traps. Severus would not be able to return.
Black splotches had settled in the Restricted Section of the library. Minerva wrapped the shelves in an extra layer of protection against curious young hands, resolving to search through those books with Madam Pince before the fall semester. The DADA classroom was splattered with darkness – spells, curses, student duels gone too far and the lingering smell of Dolores Umbridge's evil tainting every surface. Minerva slammed the doors, set the wards to full, and sent a purging fire to burn up every atom of substance and air. She did the same for the pink toad's office, one floor above. Untouched since her removal, the bitter taste of her dark artifacts fired Minerva's rage even hotter. Hogwarts seemed to approve as it added to Minerva's fire with a white light, purifying the bare stones that were all that remained.
Her focus skirted along hallways and staircases, erasing the taint of a hex here, the lingering stain of a spilled potion there. As Minerva submerged herself within Hogwarts, the castle's magic put down deeper roots within her as well, its satisfaction with her fiercely protective attitude causing unexpected changes. Aches and pains lessened, the tightness in her chest eased, and she felt her heart strengthened, beating more effectively as arteries and veins were cleansed. As she vowed to sustain Hogwarts and protect its charges, so Hogwarts opened all of its magic to her, giving her access to powers long unused and corridors and wings long inaccessible.
As Hogwarts opened itself to Minerva, one final spot of darkness appeared. Black and green, a festering wound, a gaping tear in Hogwarts' wholeness appeared. Seventh floor. Behind a blind wall – no, a room appeared on her inner map of the castle. A room that was tied more tightly to the castle's magic than any other, including the Headmistress's office. A room that could only be accessed at great need.
Both hands on her wand, Minerva let the castle whisper its secrets about the Room of Requirement. A frail memory was teased to the surface of her mind, the memory of Albus speaking of a room full of chamber pots, of her school-friend Martha describing a vivid dream of stumbling into a room containing a muggle telephone that connected her with her dying grandmother for one last talk, and, finally, of Harry's secretive club dedicated to training themselves for battle.
Here lay the final item – an artifact wrapped in curses, radiating death. She and Hogwarts built up complex wards, trapping the thing in an impenetrable cage of power. It rattled and banged, hurling power against her, trying to wrap itself in the guise of a harmless token, or a priceless historical relic. She would not be fooled.
"Headmistress."
Minerva opened her eyes, Hogwarts holding her magic steady as the ghost materialized before her.
"Grey Lady. Helena," she corrected herself when the castle offered up the Ravenclaw's ghost's name. "You speak?" She had been silent for centuries.
"Destroy it, Headmistress. Remove the sin and stain, I beg you."
"Has this thing trapped you here, my Lady?" Splitting her focus between the ghost and the dark artifact, Minerva realized that the thing had taken its final shape. A jeweled crown. A – "The lost diadem of Ravenclaw."
Hogwarts itself crushed the thing to bits without one spoken or unspoken spell. Fiendfyre did the rest. A scream pierced the castle, echoing from the stones and along the hallways. Minerva watched Helena Ravenclaw's ghostly form shiver and shake, silver tears leaking from behind closed eyes. As the echoes of the scream died away, the other Hogwarts ghosts appeared, the remaining House ghosts huddled around Helena, the Bloody Baron folding one arm around her misty shoulders.
"We are at your disposal, Headmistress." The Fat Friar bowed his head. "All of us stand ready to aide Hogwarts and her students."
Minerva straightened. "I accept your fealty. For now, I send you to search every hallway, nook, cranny, secret passage, and cupboard for weakness. Weakness in our wards, in our stones and floorboards, in the magic and material that makes up our home. We shall not fail."
She stood for another hour, rewriting protective spells, warding secret passages to respond only to Hogwarts' children at need, and reminding the very stones and stairs that its loyalty was not to the memory of Albus Dumbledore, but to young witches and wizards who called the castle their home.
Hogwarts glowed with life, eager for the changes, the stones shimmering with the witch's magic, welcoming spells laid down with power, with intention, and with a greater heart than it had felt in hundreds of years. When the magic settled, she cast three Patronuses in rapid succession. "To Filius, Pomona, and Horace." Both hands on her wand, McGonagall issued her orders. "To me," she commanded. "At once. There are Hogwarts' children in danger."