The Price of Atonement by Eihwaz Ehwaz

Of all the holidays Severus Snape detested, a number which included practically every holiday one might care to name, none was more loathsome to him than Halloween. It was the day the Dark Lord had been temporarily unbodied, true, and he had once made a point of toasting that fact privately ever year. However, the man—no, the fiend—had returned, so as far as Snape could see, there was no longer any cause for celebration. Besides being the anniversary of Lily's death (as if that on its own were not reason enough to loathe the day) it was also the day when the veil was thinnest. Any number of spells, potions, and rituals concerning the dead could be enhanced by completing them on this day, most of them dark or nearly so. There were even a small number that would be unsuccessful on any other day of the year, all of them illegal.

Any sensible adult in a school full of dunderheaded children would have spent the evening assuring that no such spells were attempted. But Dumbledore, great wizard though he was, did not quite fit the definition of sensible. Instead of tightening security, he held a feast, extending curfew and thus ensuring that there would be enough low-level chaos in the evening to make it difficult to spot a student plotting.

Perhaps, Snape mused after finding yet another student out of bed after hours and sending the wandering Hufflepuff to the hospital wing to secure a potion for his stomach ache, Dumbledore's idea was not so much to entertain the students as it was to thwart any nefarious plans by causing widespread indigestion throughout the student body.

Thankfully it was only a few minutes to midnight. Soon the danger would have passed and Snape could retire to his chambers for a glass of firewhiskey and a private toast to Lily's memory.

Or perhaps not, he thought, eyes narrowing as he felt the thrum of magic within an unused classroom. The door was locked from the inside, but that was easy enough to counter, as the classroom doors had long ago been spelled to resist the more effective locking charms unless cast by a professor. After casting a silencing charm on the door and a disillusionment charm on himself, he eased the door open and slid inside.

Potter. Of course it was Potter. The boy had inscribed quite a complicated runic circle on the floor and was standing in the center as it gathered power. In front of the circle Potter stood in was a smaller triangle of conjuration. Whom was the boy attempting to summon? For a moment, Snape considered the possibility that it might be Lily and his heart beat faster at the thought of seeing her again. He took an involuntary step closer, stumbling over a book as he did so.

He glared down at the offending object and froze in abject terror. He knew that book. Worse, he knew that ritual. Had he not researched it extensively in his sixth year? The ritual had been devised by a witch who wished to seek amends with the son who had died in an accident. Something involving the unintentional mixing of two very reactive potions and an experimental charm. Her notes indicated that he had come to her and she had been forgiven. Upon reading this, Snape thought he might use it to make amends for his slip the previous year and get back into Lily's good graces, however he soon learned the ritual had a darker side. With the exception of that original casting, every other record of the ritual being performed had been written by someone other than the one who performed it, because in each case the caster had perished.

And now Harry Potter, the Boy-Who-Lived, the blasted, bloody savior of the wizarding world was about to perform a ritual that might as well be considered nothing better than a particularly painful way of committing suicide. Using instructions found in Snape's own book—in Snape's own handwriting!

Snape might hate the arrogant, strutting boy who considered himself above the rules, but he had pledged himself to protect the child. And now, with the magic in the room reaching a crescendo, Snape knew there was only one way to do so. Sparing only half a sneering thought for how very un-Slytherin his actions were, Snape ran the short distance between himself and Potter, shoving the boy with all his might to knock him from the circle.

As soon as Potter's feet had cleared the ring of runes, Snape began the incantation, only half-surprised that he remembered it after all these years. Absently, as he spoke the Latin words, he wondered if Potter had even bothered to translate them. Probably not, arrogant fool that he was. "I call upon the spirits of those whom I have wronged!" He reached down and picked up the athame and, willing himself not to think about the fate that surely awaited him, pushed up the left sleeve of his robe and drew the dagger swiftly from the inside of his elbow to his wrist, neatly bisecting the Dark Mark with a shallow cut that nevertheless began to bleed rather profusely. Ignoring the pain, he continued, "Come determine the price I must pay to atone for my sins. I submit myself to your power and await your judgment."

"No. No, stop!" the boy shouted, but it was too late. Snape sneered at the brat, but not for long; there were more important things to worry about than expressing his disdain to the author of his imminent demise. That, and the skin of his right forearm had split open under his robes. The wound would mirror the one he had inflicted on himself, he knew.

The dead had heard and had answered. They were coming, and he would die.

Out of the corner of his eye, Snape saw Potter turn away and was glad for it. He wanted no witness to this travesty. Perhaps the idiot would even attempt to leave. As it was Potter's magic that had built the circle, the boy's leaving would cause the dome of magic to shatter, killing Snape instantly. Given the accounts that he had read of failed attempts of the Ritual of Atonement, instantaneous death would likely be a blessing.

Meanwhile, misty forms were coalescing in front of him, visible only to his eyes. Some he had known in life, such as his father, who now stood in front of him with a scowl on his face, a belt in one hand and a bottle in the other. Others he barely recognized from his past: classmates he had hexed who had died in the war, students he had tormented who had met an untimely death. The majority, however, were far more frightening. They were a nameless multitude, and the malevolence from their numbers was suffocating. His eyes darted from face to face, searching for some memory of how he had wronged them but finding nothing.

A chill ran down to the base of his his spine causing his lungs to seize as it passed them by. Potions. These were people who had been hurt or killed by potions of his making.

His breath came in quick, painful gasps as a tall, burly man steps forward from the gathering throng. With great deliberation he placed one thick-fingered hand on Snape's arm right over the bloody slash. Immediately Snape's insides were riddled with burning, stabbing pain. Intestinal Inferno, he realized, gasping against the pain. He remembered the night he presented his invention to the Dark Lord, basking in the momentary praise.

"Enjoying a taste of your own medicine, are you?" the man drawled.

Another spirit stepped forward, this one covered with open wounds. She laid her hand next to that of the burly man, and Snape felt as though deep gashes opened all over his body, though he looked down and saw only the one on his bare arm and blood from it's partner still hidden under his robe. Still, it felt like Sectumsempra. Oh, how proud he had been of that spell. Fool! "You may not have cast the spell, but you created it," the spirit said. "It took me hours to die, and I was in agony the whole time."

He didn't see the spirit third step forward until a charred hand that was more bone than flesh slipped into his field of vision. Now it wasn't just Snape's insides that were on fire but his whole body. "You helped devise the potion that cause the fire to resist all efforts to extinguish it. I died with the screams of my husband in my ears."

A wave of nausea crashed over him from the pain, but when he opened his mouth, it was not just the contents of his stomach that escaped. As his arms bled, and his stomach muscles cramped, and the phantom gashes screamed in pain, and his flesh burnt without burning, Snape began to scream.