Professor Slughorn scrambled up the stairs and fumbled for the castle's front door. He was sniffing loudly as he entered the thankfully empty front hall, the boy's words still ringing in his ears. Oh, he was an old man now, it had been a very cruel thing to do – to torture him with such horrid details... Poor Lily Evans... she and her pretty eyes and witty tongue... to die in such a way... and certainly the boy would hate him now...

Everything was swaying quite unpleasantly and it was really very hard to focus eyes in the darkness. The little lantern Slughorn was holding didn't cast a strong enough light. He struggled to see in the light of its flickering flame, but the shadows danced on the walls and along the floor, and he staggered slightly as he tried to find even footing on the treacherously slippery stone floor. It took Slughorn much longer than usual to make his way up the stairs and towards his chambers because he kept bumping into cabinets and corners which he could've sworn hadn't been there on his way to Hagrid's hut.

When Slughorn was climbing up the staircase between the third and fourth floors, his surroundings seemed to give a particularly nasty jolt – he had barely enough time to blink and register the abrupt gripping sensation in his belly - and then, to his horror, he realised that he was falling. He had forgotten about the trick step! Slughorn cried out in surprise and pain when his legs disappeared somewhere beyond the wood and carpet; his belly thankfully stopped him from slipping all the way to the floor below.

Abruptly finding himself thigh-deep in the stairway, Slughorn struggled to pull himself up; but alas, he was unable to. The lantern had fallen from his grasp and the flame had gone out, leaving him in darkness. He tried in vain to reach his wand, but it was inside the pocket that was currently inside the staircase, and he couldn't manage to wiggle his fingers around it. He was stuck. Stuck, wandless, and slightly nauseous. Slughorn let out a string of profanities which echoed on the stone walls, and some faraway portrait tutted at him in indignation.

After another moment of useless struggling, Slughorn sniffed and gave up, slumping against the stone step around himself. He could feel that one of the little flasks inside his robes had broken and the acidic Acromantula venom was slowly absorbing through his clothes, making his skin itch unpleasantly. There wasn't much he could do about it in this unfortunate position. It currently seemed likely that he would be forced to stay there all night covered in the stuff, and be found covered in blisters in the morning. He could already almost hear the ridiculing whispers of the students as they arrived to witness his hungover, blistery disgrace. Or perhaps before any students made it there, one of his colleagues would bump into him on their way to breakfast and he would turn into a joke at the staffroom, Slughorn thought melodramatically. 'Old Slugs stuck in a stair...' Just as well – perhaps he deserved it, for having been so very, very foolish... to have fallen for the polite charade... to have fallen for the flatteries of a madman... he sniffed again, feeling quite sorry for himself.

"Horace?" He suddenly heard a soft voice from behind himself. He struggled to turn his head in an angle where he could see the source of said voice. The face of Severus Snape appeared in front of him; the younger man was standing at the bottom of the stairs, eyeing him blankly. He had appeared soundlessly, wasn't carrying a light, and it rather appeared as though he had simply condensed himself into existence out of the very shadows surrounding him.

"S-Severus?" Slughorn slurred, feeling rather foolish under the unblinking gaze of the black eyes. The situation was made worse by the unwelcome tears which had right before Severus's sudden appearance begun to well up behind his eyes as he had pondered at all his mistakes.

Severus didn't ask him what he was doing out so late, nor why was he loitering inside a staircase in the middle of the night. He just quietly glided to Slughorn's side and offered him his hand. With his help, Slughorn managed to worm himself out of the staircase, which promptly closed up and re-assumed the appearance of an innocent, regular stair. Slughorn wiped his brow, staggered for a while (Severus grabbed him by the shoulder to steady him) and then tried very hard to hide his puffy eyes and wet pocket from the penetrating gaze of the other man.

"Thank you, thank you, my dear boy..." Slughorn said as he straightened himself, and then felt even more foolish. Severus Snape was no longer that gangly, boyish teenager he had once been, and addressing him as 'dear boy' seemed to be in violation of something very profound in the black-clad, severe looking man. Slughorn peered at his rescuer pensively, trying very hard to focus his eyes upon the man's features. Had he always been this... dark? Had he always had that bitter crease between his eyes?

To his horror, Slughorn realised he had pondered all this out loud.

Severus Snape raised his eyebrows and examined him rather coldly. "I believe you have had a drink too many, Horace. Perhaps a dose of Hangover Vanish and sleep would be in order?"

Slughorn sniffed. "My dear boy... eh... Severus... I deserve the hangover! I've been such a fool... but you wouldn't understand..." he wiped his nose, feeling tears rise to his eyes once more.

"However you like. Would you like me to escort you back to your chambers?"

Severus jumped slightly when Slughorn suddenly grabbed him by the front of his robes. Slughorn looked into the unnerving black eyes through a haze of tears, and shook the man by his lapels.

"But you knew her, Severus, you did, didn't you?"

"Knew who?" Severus asked in an irritated tone of voice, prying Slughorn's fingers off himself. The older man didn't let go.

"Lily... Lily Evans... I mean, Potter - Harry Potter's mother - you always sat next to her, you exchanged those little notes behind my back, I saw it... little Lily Evans, with red hair... you knew her, you knew what a wonderful girl, a wonderful witch she was, didn't you?"

Severus froze, his fingers around Slughorn's wrists, and Slughorn stared at him pleadingly. Oh, to be able to tell Severus, to tell anyone what a wreck of a human being he had been...

"I did," Severus said quietly, his lips hardly moving. He said it as though he was confessing to a grave sin.

Oh, to confess! Slughorn craved to confess, to confess and then be freed of the burden of a guilty conscience; he wished for an absolution of the sort that only someone who fully understood what had once been and what had been forever lost due to his misguided foolishness could give him.

"I didn't mean to... I never imagined... Tom was always such a pleasant boy, a polite boy," Slughorn pleaded for Severus's understanding. "Never in trouble! Perfect marks, every time! And so thoughtful, always a bag of dried pineapples for special occasions... so when he asked... I should've seen... such dark magic and then she... she... perhaps she wouldn't have died if I hadn't told him..."

A lump in his throat made it hard to speak, and he swallowed. Severus's hands had fallen to his sides, and he no longer tried to pry Slughorn off his robes.

"I always liked little Lily Evans..." Slughorn pleaded. "So vivacious, charming, compassionate... perhaps my favourite student out of them all... Severus, I can't stand it – I never meant... to give Tom information like that, I fear I did worse harm than any Death Eater... and I never wanted anything to do with that lot – ouch!"

Severus had abruptly grabbed Slughorn's arm into a harsh grasp, and his eyes, which before had looked unreadable, were now alight with a dark flame. Slughorn took a step back, suddenly frightened of the man.

"What did you tell him?" Severus hissed. "Tell me everything!"

"I – no... I shouldn't... not to you – you..." Slughorn peered at the man through his tears, suddenly remembering. "Weren't you a Death Eater once, too? Weren't you accused -"

Severus's grasp tightened around his arm; it was quite painful now. His eyes were gleaming in the darkness, his face so full of some emotion Slughorn couldn't quite understand that he looked frightening, mad...

"Tell me!" Severus ordered, and the image of Tom Riddle's handsome young face surfaced in Slughorn's mind...

Can you tell me about Horcruxes?

"What are you - ", Slughorn started weakly.

"Horcruxes?" Severus whispered, his eyes blacker than ever, like two endless tunnels where Slughorn was falling. He was helpless, his own words from decades ago ringing in his ears...

"But I didn't mean to!" Slughorn repeated in a shaking voice, trying to push the shameful memory away. "His charm was just too hard to resist! If I could go back... Severus, dear boy, if only I could bring her back to life -"

"She's gone," Severus said flatly, interrupting Slughorn's string of pleading words. Slughorn thought he looked oddly vulnerable as he said it, not at all like his usual self. "Dead. Forever gone. Because of foolishness, because of desire for glory and power..."

"I had no desire for either glory or p -"

"Why did she have to pay for the mistakes of so many?" Severus cut him off, his face distorting with some repressed emotion as he stared at the wall behind Slughorn. "Why did she have to go, when so many others would have deserved to go in her stead?"

The tears came again, and Slughorn choked back a gravelly sob. Severus didn't understand, couldn't understand... oh, how could he?

"Harry told me today..." Slughorn croaked. "H-he told me how it happened... I asked him to stop, I am an old man, I did not wish to hear... but he told me how his father died first... told Lily to escape, to take Harry and go... a-and Harry told me... he told me that He-Who-Must-Not-Be-Named told Lily to step aside, that she died begging him to spare Harry's life, offered her own life in exchange for his... and... and then he murdered her... laughing..."

Severus let go of Slughorn and turned his back on him. Staring at the back of his head, Slughorn rubbed his bruised arm. He swallowed his tears and hiccuped, thinking of the clever girl who had always made him laugh... who had been annihilated in such a cruel way...

"I think she would forgive you," Severus said very quietly. He was speaking to the wall in front of himself. Slughorn blinked. "I think... if... if she knew how deeply you regret... if she knew that you regret it more than anything... that you only wished for her to live and be happy at any cost to yourself, wanted it more than anything else..."

Slughorn hiccuped again. He had a bizarre feeling that Severus had slightly misunderstood the strength of his devotion and familiarity towards the dead woman. But the ray of hope he was granted was a relief and he eagerly consoled himself with Severus's words.

"Yes, she would, wouldn't she?" Slughorn agreed gratefully, clinging on to the absolution Severus had offered him. After all, Severus had known her, had once been her friend. If he thought she would forgive him, certainly he would be right. "Lily was such a kind person... if she knew I would never do it again... I mean, we're all just humans... if she knew how I regret it now... she wouldn't judge, would she? She wouldn't think too badly of me, would she?"

"No..." Severus muttered. "No, I believe she would understand... and forgive."

The two men were quiet for a long while after that. Severus stood with his back on Slughorn, and the older man could only guess at what he was thinking. He really was quite a cryptic person, Slughorn thought. But as Slughorn thought of what Severus had said, he felt a little better about everything that had transpired. After all, Lily Evans had been the sort of person who had valued reformation, had always wanted people to improve, and had always been willing to give someone a second chance as long as they took responsibility for their actions...

"I should escort you to your chambers now," said Severus.

He turned back towards Slughorn. Slughorn squinted at him, trying to guess what the man was thinking, what he thought of him, but Severus's face was unreadable and closed off. Together they started walking upstairs towards Slughorn's chambers, the other teetering uncertainly and grabbing the occasional wall or marble bust for support, the other gliding soundlessly over the stone floors. Finally they reached the door of Slughorn's sleeping chambers. Slughorn was just about to turn around and ask Severus what he himself had been doing up so late, wandering about the upper floor corridors, when he suddenly felt Severus's wand touch his shoulder. Slughorn opened his mouth in indignation to ask him what he was d -

"Obliviate," a soft voice whispered. Things became blurry, fuzzy, the corridor swayed harder than ever, as though he was riding the waves out on the open sea... it felt like all burden was lifted from his shoulders... oh, how sweet it was to forget...

When Slughorn came back to himself he wondered why he was standing outside his chambers in pitch black darkness. And why was his head hurting? And why did his leg feel damp and burning, like it had been dipped into something mildly corrosive? Goodness, he must have had a drink too many.

Slughorn could have sworn he saw, out of the corner of his eye, a shadow move across the moon-lit corridor – but as he turned around to look, he saw only an empty corridor shrouded in darkness.

His heart felt lighter than it had in a long while.