Chapter 1: Snape's Chambers
He was asleep, a rare occurrence at the best of times. Flitwick's knock, not entirely unexpected, arrived seconds after McGonagall's charm roused him from his dreams. "Professor Snape, you must come. It's Albus. He needs you."
"Damn you Albus." He swore under his breath as he dressed hurriedly, then opened the door to let in the pintsized Professor Flitwick. Flitwick, who only came up to Snape's knee, levitated to the bureau to look him in the eye, too winded to speak. The goblinlike professor simply panted, opening his mouth and closing it uselessly a moment.
"Is Draco Malfoy out of bed?"
"I didn't check…."
Snape snapped his fingers for his wand. "Potter? Is he roaming the halls?" That would be all he needed, tonight. He passionately hoped that Potter was where he was supposed to be, or the whole night would be for nothing. Flitwick said, "He's with the Headmaster. And there are people in the castle….DeathEaters." Snape whirled on Flitwick with blazing eyes. "Petrificus Totalis!" he cried, and Flitwick fell to the floor with a thud.
"Sorry, Filius, old boy, can't risk you being hit," he muttered. He rushed out of his room, saw Luna Lovegood and Hermione Granger, and barked at them, "Professor Flitwick is ill-see to him!" They bolted for his study. That was three of them out of the way, at any rate. He doubted he could do anything about the melee in the corridor.
Grateful that none of the others could possibly penetrate the barrier placed by Amycus, he sprinted effortlessly through the it and ran after the Deatheaters and Draco, to the tower where Dumbledore lay waiting. He prayed that he did not come too late.