Albus Dumbledore had not expected his day to go like this. All he had wanted to do was sit in his office, have a cup of coffee, maybe a lemon drop or two- if he felt daring enough, perhaps a few Bertie Bott's Beans- and relax for once.
But no, that would be asking too much. He thought, sardonically as he walked quickly down the length of the corridor, hearing the screams bouncing off the walls, as if making a statement of how incompetent he was. The hallway was ice cold and reeked of death, neither of which he noticed. He could hear the water dripping from the ceiling under Moaning Myrtles' flooded bathroom; it only added to the feeling of dismay.
Albus was unprepared for the scene that greeted him. Utter chaos had broken loose in the great hall; students and faculty alike were sobbing uncontrollably, helplessly as dementors patrolled the aisle.
And he remembered. He stumbled backwards, feeling an ache in his chest worse than if he'd been hit physically. Terrible memories raced through his mind. The bodies of thirteen people laying dead in a street, with an innocent man laughing manically, of the same innocent man falling through a veil that he would never return from, and of his godson watching in terror.
The dementors grew closer, he could see their bony hands clench in perverse anticipation; satisfaction.
He saw Death Eaters' funhouse in his minds' eye, with a man shackled up against the wall, bleeding from numerous unidentifiable places, sobbing as he looked at his sodomized and murdered wife on the table before him. He saw Ginny Weasley's limp body carried by an exhausted and bloodstained young man.
He felt a dementor lean down towards him, as he saw... He saw Tom Riddle killing Sylvia, and laughing at Dumbledore's young form as he watched his wife die... Dumbledore smiled faintly; he would finally-
"EXPECTO PATRONUM!" Albus saw Minerva McGonagall's silver lion charging at the dementors.
"Albus!" Minerva panted, her hands shaking, "Flitwick... Dead. Snape went... hold off dementors outside..."
Albus nodded, getting nauseous, as the dementors recovered, and began to move again. He could hear his wife's scream echo in his mind as Tom tortured her, as Tom goaded him, as Tom broke her down before murdering her.
"Expecto... Expecto Patronum," Albus heard Minerva say beside him, but nothing but the faint image of a bear appeared. The dementors grew closer as Albus raised his wand. He thought of the day he had asked Sylvia to marry him...
"EXPECTO PATRONUM!" He roared, and a silver dove flew at the dementors, driving them back towards the wall. He watched as the dove circled around them, pecking, unbiased.
A lone dementor made one last attempt towards Albus, but was deterred by the dove, which flew towards the dementor, and circled around it. The dementors glided out of the open window of the great hall, as the dove cooed once, and faded into smoke.