Severus Snape was a boy who didn't believe in petty little charms as proper revenge. No, the best revenge was served perfectly crafted, cold and unexpected, with leaving the victims ruined, helpless and disgusted with themselves.
It had taken him weeks to plan how he would do it. There were so many delicious, tempting ideas he had and it had been hard to choose between them. The promise he had made for Dumbledore was but a small obstacle in his way. "I will not hurt physically or magically Remus Lupin, Sirius Black, James Potter or Peter Pettigrew", he had promised the old man, "I will not tell anyone about Remus Lupin's lycanthropy, not with words spoken or written." The hardest part had been keeping his face straight and to not burst out laughing. Didn't the old fool see the many ways he could get around that pitiful oath?
Apparently not.
As Severus walked back to his dorm the night when his careful plans would finally come to fruition, he couldn't help but rub his hands together and smirk.
Tomorrow morning would find the so called 'Marauders' thinned and nobody could prove it had been Severus. He knew that there would be an outright war after this between him and the remaining prats, but he would be ready.
And if he was lucky, those who survived this night would be too broken to retaliate and instead would kill themselves in their sorrow and shame. And at that thought, if anybody had been awake and withing the hearing distance in the dungeons, they would have heard Severus Snape losing it and laughing evily until he was out of breath.
The next morning Severus couldn't believe his eyes as all four of the Marauders walked inside the doors of the Great Hall. They looked exhausted and there were new scars on Lupin's and Black's faces, but they were all alive.
Severus spent the breakfast ignoring their murderous glares and thinking frantically through the spells he had used and the precautions he had taken. He had been so certain he hadn't missed anything, that there hadn't been any loopholes...
He managed to avoid Black and Potter most of the day, but they caught him when he was sneaking to dungeons to eat lunch from his prehoarded rations. And then it was too late to realize that he should have fled the castle hours ago, when he still had had a chance.
Punches, kicks, one broken wand later, as Severus was lying on the cold stone floor, Black kneeled above his body and sneered at him. "Thought you were clever, huh? Thought you had us? Locking us up wandless with a werewolf during the full moon."
Severus spat at his face and got a kick to his stomach from Potter.
As Severus took labored breaths through his broken ribs, he heard Potter say: "I should have never saved your life, you scum."
Black let out a mirthless laugh. "So thoughtful and sweet of him to leave us with a gun and silver bullets, though. How should we thank him for that?"
The clicks of the gun opened and then loaded were loud in the empty hallway. "I think I'll thank him by taking my mistake back", Potter growled.
"Dumbledore-", Snape groaned, but the boys only laughed.
"Oh, we'll be gone by the time they find your body, don't worry."
