“Ron!” Harry said anxiously the next night, shortly after curfew. He was sitting on his bed and flipping through a few sheets of parchment. “My last page of research is missing. I can’t finish my essay without it.”

 Ron, who was also hastily scribbling away from where he sat at the small table in their dorm said, “You can take a look at my research.”

 “No, I can’t, Snape assigned us different topics,” Harry moaned, putting his quill on the side table and falling back into his pillow. “I’m dead.”

 “If only the dungeon bat hadn’t told us to hand it in so early, and on a Sunday too,” Ron griped. “I’m pretty sure it’s a crime to make someone get up at six-o-clock on a Sunday just to hand in a stupid essay. Evil git.”

 “I suppose I could just make some stuff up ... but he’d probably make me redo it.”

 “Well, you do have an invisibility cloak now, you know,” said Ron in a hushed tone. “How about going to the library tonight? I mean, it isn’t as though this is your first time sneaking out.”

 “Oh sure, and it went so well the last time I went looking for a book in the middle of the night!” spat Harry.

 “Come on, that was the restricted section. It’s voodoo to try and sneak in there, even during normal hours. Besides, Fred and George told me that Filch barely patrols the rest of the library at night - he thinks none of the other books are worth reading after hours.”

 “I’d still rather not take my chances at having a run-in with Filch, thank you very much.”

 “Well, it’s Filch or Snape. Take your pick.”

  ***

    Click … click, click-click, past Professor Snape’s office. A black shadow passed in front of the door. Click, click … click-click against the stone, echoing off the walls. Abruptly, a light shone from beneath the door to Snape’s office.

      “Who’s there?” called the tired voice of Professor Snape as he pushed the door open. 

      The clicking died away around the corner. The light flooding from the doorway chased away the darkness, but nothing was there.

 ***

 The clock struck one. At last the sound of the door shutting to the older boys’ dorm echoed off the stone, and Harry crept out of bed and threw his invisibility cloak over himself. With his book bag over his shoulder, his parchment and quills inside, he tiptoed down the staircase. He let out a silent breath of relief when he saw the common room was indeed empty. It would not do for someone to see the portrait hole opening on its own. Looking this way and that, Harry walked softly across the common room.

 Something jumped out at him and hissed, and he nearly shouted with fright.

 “Go away Hermes,” said Harry in a hushed voice directed at Katie’s cat as it stood in front of the portrait hole, its fur bristling, spitting and hissing.

Harry pulled the cloak off.

“See, it’s me you silly cat.”

 Hermes still didn’t move, and instead took a step toward Harry, who backed up slightly. He frowned, and bit his lip, looking at the clock. He turned around and grabbed a blanket off the couch. Looking guilty, he threw the blanket over the cat.

 Hermes let out an undignified meow as he tried to get out from under it. Harry took his chance, and he leaped over the thrashing cat and pushed open the portrait hole, his invisibility cloak on once more. Cheeks flushed and panting slightly, he did not look back as he started down the corridor. He went cautiously and carefully, but he really needn’t have, as the corridors were empty wherever he went. It was silent as the grave, except for the occasional whistle of wind rushing through the long, draughty corridors. Despite the emptiness of the castle, Harry still whirled around every so often, eyes scanning the floor for the swish of Mrs. Norris’ tail, looking sure he had heard the patter of her paws on the stone. But each time there was not a soul in sight. Despite this, Harry practically ran for the door to the Library when it came into sight. After a hurried Alohomora, he opened it carefully to avoid squeaking, despite his eagerness to get through the door. Closing it behind him, he let out a sigh of relief. Now all he had to do was find the book.

***

A figure rushed through the halls, sweaty and panting. Professor Snape was wearing a long grey nightshirt, no shoes on his socked feet, and was holding his wand aloft. He paused to peer around a corner. In his other hand was a lit lantern, light spewing out from it, leaving his wand free to fire a curse at any moment. Snape looked ready to hex the nearest thing that moved. Lantern swinging, he rushed around the corner once he determined nothing was there. Somewhere beyond the reaches of the light, something made a rustling noise, followed by a series of clicks. The sounds were foreign to the halls of Hogwarts, and seemed to greatly worry Professor Snape as he traced the path to the Headmaster’s office with his hurried steps. The empty floo powder pot on the mantle in his quarters told the story of why he was venturing through the castle, despite the fact that there was clearly something wandering the halls. Corridor after corridor he went through, winding his way through Hogwarts, all the while acting as though a demon were on his heels. Click, clickety-click. Whatever it was was still there, and it seemed to be moving in a similar direction as him, and sometimes it sounded as though it were coming from two places at once. Snape spun around as the clicking sounded once more. He swore quietly when there was nothing there but the lantern light bouncing off the looming suits of armour. His eyes lingered on the dark gaps in their helmets.

“Almost there … almost there,” he whispered shakily to himself. He only had to go up one staircase and down one last corridor, and he would be at Dumbledore’s office.

 His feet continued to move at a fairly steady pace, though Snape seemed to be trying to refrain from running at the sight of the staircase. Halfway up it there was a strange whoosh and the clicking sounded once again. Wand ready, Professor Snape turned to look for it again, and this time his eyes widened. He took a hasty step backward when he saw a shadow on the wall cast by his lantern. He tripped on the stair and fell, narrowly saving his source of light. Whatever it was had gone, but a green tinge had appeared on Snape’s skin despite the shadow’s retreat. It was then that he began to sprint. The sound was there again, but he did not turn around to see what it was.

 “Chocolate Frogs!” he cried at the gargoyles, which jumped aside for him. Snape ran up the spiral staircase two steps at a time and hammered on the door of Professor Dumbledore’s office. “Come on … come on …” he muttered under his breath.

 “Whatever is the - “Dumbledore began, looking tired in his purple dressing gown. Snape pushed past him with impressive speed and started pacing with a vengeance. “What is the matter, Severus? You look awful.”

 Professor Snape panted a little, trying to calm his breathing. This only made him look more hysterical, wearing only his nightshirt and socks (one half off), still gripping the lantern and his wand tightly.

 “Shut the door,” he hissed, staring in barely concealed horror at the gaping entrance as though he expected something to come through it. He proceeded when the door was closed, looking around frantically. “There’s something in the castle. I could not sleep, so I was sitting in my office. I was just about to turn in when I heard clicking by the door, like claws on stone … and on my way up here to tell you about it something was following me. I - I’m sure of it. Then I saw a shadow on the wall, and I swear on my mother’s grave it was a werewolf. I swear, Albus.”

 “Calm down, Severus,” Professor Dumbledore soothed, pulling out a chair for Snape as he surveyed the dishevelled appearance of the potions master: the thin sheen of sweat on his skin, the wide eyes and shaking hands.

 “I’m not making this up Albus,” he croaked, not taking the chair, but letting Dumbledore pry the lantern from his grasp and set it on the desk. He barely seemed to notice, in fact.

 “I’m sure you did see something that looked to you like a werewolf’s shadow,” said Dumbledore calmly, “and I’m sure you did hear something in the hallways.”

 “It was a werewolf shadow,” Snape said defensively.

 “Have you thought that it might have just been one of the students’ cats making the clicking sound, and the shadow was something that only looked like a werewolf, and was really something else? The imagination plays tricks at night - surely you know this.”

 “I do!” spat Snape, yanking his shoulder out from under Dumbledore’s hand. “It wasn’t a cat making those noises, and if it was it had to have been the size of a cougar at least!”

 “I’m not saying you didn’t see what you say you did … but I would like to remind you that you did let your imagination get away with you a bit as a student on matters like this. Is it not possible that this could be -”

 “I’M NOT A STUDENT ANYMORE, ALBUS!” bellowed Snape, hands clenched, furious. “Just because of what happened that night in the hospital wing after Black tried to kill me, does not mean I can’t spot the real thing! That was one time! ONE!”

 “Severus,” began Dumbledore.

 “Do not Severus me! I saw what I saw, and if I was right, which I am this time, then the students are in danger. You can refuse to believe me, but are you really going to gamble lives over this?”

 “Severus,” said Dumbledore in a soft, but dangerous voice. Snape appeared to sense that he shouldn’t go any further, and fell silent. Though this did nothing to extinguish the smouldering fire in his eyes. “You aren’t giving me a chance to speak.”

 Snape looked as though he were barely holding back the poisonous retort he longed to spit at Dumbledore.

 “Look outside,” said Professor Dumbledore softly.

 Mutinously, Professor Snape stalked over to the window and looked out. His shoulders drooped slightly.

 “But -” he started before faltering, unable to finish his sentence as he looked out at the moon.

 “The full moon isn’t for five days. There could not possibly have been a transformed werewolf in the castle.”

 “I know what I saw …” Snape said, this time softy.

 “Perhaps we should just let this one go. It’s been a long week, we’re all tired.”

 “I -”

 “Go back to bed Severus,” Dumbledore responded kindly, offering the pot of floo powder to Snape, who looked puzzled.

***

     Deep in the library, Harry hastily skimmed through a book, his invisibility cloak left on the floor. The only light came from the lantern on the table, which was turned down to a low flicker.

    “Ah, there it is,” he muttered before scratching down some information, the noise sounding like thunder in the silence. And while it only sounded loud because of the stillness of the castle, the noise was just enough to cover the rustling that was growing at the front of the library.