"Yes, ma'am?"

Harry Potter faced Minerva McGonagall respectfully across the solid width of the Headmistress' desk. In the portrait above her chair, the image of Albus Dumbledore slumbered peacefully. Harry couldn't help swallowing hard—again—every time he'd looked at the portrait today. He wondered if he'd always have that same reaction.

"I was wondering, Potter, if you could explain this?"

Harry dragged his attention away from his former Headmaster's image.

Professor McGonagall was holding a flask between her thumb and fingertips.

A familiar flask, Harry realized with a jolt. The flask that Hermione had conjured in the Shrieking Shack—how many hours ago? It seemed like years. Harry stared at it, remembering. A shudder rippled through his being before he could repress it.

Snape…

"The reason I'm asking, Potter, is that the gargoyle informed me that you had entered this office in the middle of the night." She examined Harry steadily. "Did you happen to leave this flask here?"

"Well, uh—yes. I suppose I did."

"I see." McGonagall tilted the flask and Harry saw something shimmer in the bottom of the clear glass container. "And what, might I ask, is in it?"

Mm…" Harry hesitated. "It looks like a memory to me."

McGonagall frowned. "Of course it's a memory, Potter! My question is: WHOSE? And why did you leave it on my desk?"

Harry shook his head in confusion, sending his tousled black locks into further disarray. "I'm not sure, Professor." He hesitated again. "I'd assume it would be Professor Snape's memory, but I thought I'd put all of his into the Pensieve already." He stared at the swirling substance, undulating with a seeming life of its own. "I'm not sure about that one—unless it got—stuck?" He wondered if that was even possible. "If so, then I never got to see it. And he'd wanted me to."

Silence fell as the Headmistress and The-Boy-Who-Continued-To-Live-Despite-All-Odds studied the contents of the flask.

"Then I suppose you had better see it," pronounced McGonagall, handing the flask to Harry, who cringed as he touched the cold glass.

Did he even WANT to see another of Snape's memories? Of course, he tried to reassure himself, with Voldemort finally Dead-And-Gone-Forever, maybe this particular memory was moot. Maybe … Harry suddenly thought, brightening a bit … maybe it was another having to do with his mum. That would be worth seeing.

He made his way slowly to the Pensieve. Before pouring in the new memory, Harry turned to look at the Headmistress. "What about Snape's other memories…?

"I've already viewed and removed PROFESSOR Snape's memories from the Pensieve," she informed him. "I'm preserving them for the Ministry of Magic. I'm certain they will serve admirably toward clearing Severus' name." Her spine stiffened. "And I intend that his name SHALL be cleared, Potter. We owe him that debt many times over."

Harry nodded in heartfelt agreement. "Good."

He turned his attention to the Pensieve. Carefully, he upended the flask, noting that the memory seemed inclined to cling to the glass, as if it didn't wish to be viewed. Suddenly, Harry recalled a single strand of memory creeping from Snape's left eye, moments before the man fell still. Harry had collected the strand, as he had the other memories which Snape had purged en masse. Was this the same last memory? One that Snape might have initially hesitated to relinquish? Was that why it had clung to the inside of the flask? The final bit of living memory, grudgingly offered up as Snape's physical life ebbed to naught?

Harry tapped the flask, the vibration nudging the memory gently toward the mouth of the container. Two more taps and it finally overspilled the lip and trickled smoothly into the swirling medium within the Pensieve. With a final glance at McGonagall still seated behind her desk, Harry took a deep breath, gave the Pensieve a stir with the tip of his holly wand, then plunged his face into Snape's memory.

He landed in the sixth floor boys' bathroom.

Snape was kneeling over Draco Malfoy, tracing his wand over the deep wounds that Harry's Sectumsempra Curse had made, muttering an incantation that sounded almost like song. The flow of blood seemed to ease; Snape wiped the residue from Malfoy's face and repeated his spell. Now the wounds seemed to be knitting.

Harry saw his memory-self watching the scene in absolute horror, and his own stomach knotted as the memory of that horror swept through him again. If only he'd never cast Sectumsempra! If only he'd listened to Hermione and returned the Advanced Potion Making text to Slughorn at the beginning of the year. Hermione's judgment was so superior to his own—why hadn't he listened? So what if Malfoy had been in the act of casting the Cruciatus Curse at Harry—Sectumsempra was every bit as bad, in Harry's opinion. And he'd been stupid enough to cast it without knowing what the Curse even did. That error of judgment could have proven fatal.

Before him, Snape had half-lifted Malfoy into a standing position.

"You need the hospital wing," Snape told Draco. "There may be a certain amount of scarring, but if you take dittany immediately, we might avoid even that…. Come…."

He supported Malfoy across the bathroom, turning at the door to say in a voice of cold fury, "And you, Potter… You wait here for me."

Harry stared at his memory-self a moment longer—the memory-Harry stood shaking as he gazed down at the wet floor where bloodstains floated like crimson flowers across its surface.

Harry turned and followed Snape and Malfoy, glad to see the door shut on Moaning Myrtle's wails and sobs.

Snape's arm supported Malfoy as they traversed the corridors, Draco's feet stumbling erratically upon the ancient stones. Students dodged to each side, staring at the bloodied blond Slytherin but avoiding the Head of Slytherin's black glare.

"What HAPPENED in there?"

Snape's voice, half-whispering, was so quiet that Harry could only just make it out, in spite of following the man so closely that—had this been reality instead of a memory—Harry would have been treading upon the trailing hem of Snape's long robes.

"What HAPPENED, Draco?" Snape demanded again as they turned a corner. The hospital wing was three floors down, at the other end of the castle from the bathroom. The trio pressed on.

"Potter," gasped Draco, between ragged inhalations. "Potter cursed me."

"Obviously," grated Snape. "Why?"

"Don't—know," whispered Malfoy, almost going to his knees. Snape hoisted him up again as Harry waited.

"Just went to use the loo—"

"Are you certain about that?" growled Snape fiercely.

"Uh—"

Harry could almost hear Draco's brain working, trying to come up with a plausible explanation. And Harry could already tell that whatever Draco produced, it would be a LIE.

"HAD to go. FAST. Emergency." Malfoy darted a sideways glance at Snape. "Couldn't wait. You know."

From the glance Snape returned, Harry could see that the man's thin lips had nearly disappeared as he compressed them.

"So you went into the bathroom. Why was Potter there?"

Malfoy did fall this time, in spite of Snape's grabbing for his arm.

"How the hell should I know?" Malfoy snapped, gasping for breath as he tried to push himself up onto his hands and knees. "Who knows what goes through Potter's mind?"

"Indeed."

Snape lifted Malfoy to his feet once again.

"I mean," continued Malfoy, staggering toward a downward staircase, "for all I know, Potter may have come in there hoping to molest a First Year."

"WHAT!"

Snape and Malfoy paid no heed to Harry's unheard shout of outraged protest as they awkwardly negotiated the steps down to the fifth floor.

"Potter?" snorted Snape. "Do you truly think so?"

Malfoy stumbled to a halt at the bottom of the stairs, glaring at Snape from beneath his bloodied blond fringe. "Anything's possible," he grunted, his pain-ridden breath hissing between his teeth.

Snape grimaced and herded Malfoy onward to the next set of stairs.

"On second thought, I suppose one shouldn't arbitrarily presume Potter to have a young man's

usual personal preferences, simply because he's the Chosen One," Snape sneered.

"Oh, GREAT!" fumed Harry. "Filthy, greasy GIT! How DARE you SPECULATE like that! About ME! To another STUDENT! To MALFOY! I don't care if you ARE the bravest man I ever knew—I could still have you SACKED!"

They'd now reached the fourth floor.

And then, Harry remembered: In reality, Snape was dead.

"Being DEAD still doesn't excuse what you DID!" he shouted in frustration, aiming a sharp kick at Snape's shin, but his foot passed through thin air instead of solid flesh, nearly throwing Harry down upon his face next to Malfoy, who had finally collapsed onto the bottommost step.

"Can't—make—it—" the blond wheezed, clutching his stomach.

Snape produced his wand from within the gloomy depths of his robes and conjured a stretcher. He lifted Malfoy once more, settling him securely onto the hovering platform. Then, Snape levitated the stretcher down the length of the final staircase. The door to the third floor hospital wing loomed ahead, bright sunlight spilling into the corridor as they approached.

Madam Pomfrey scurried to check in her latest patient, and ran a quick diagnostic on Malfoy after Snape had charmed off the boy's bloodstained shirt.

Harry cringed at the brutal-looking weals on Malfoy's pale chest and stomach. Snape's counter-curse had mercifully closed the wounds, but the scars still showed redly-raw against white flesh.

"Start with his face," Snape directed the medi-witch, as she conjured vials of dittany potion as well as a dittany salve.

"Drink up, Mr. Malfoy," Madam Pomfrey ordered, holding a vial to Malfoy's lips.

Draco swallowed the first vial with a deep shudder, then very nearly gagged at the second dose.

Harry couldn't really feel sorry for that, not after Draco's false accusation that Harry might have intended to molest a younger boy.

Madam Pomfrey immediately began to smear a thick greenish salve over the scars on Malfoy's face, coating them over so heavily that they couldn't be seen.

Harry reached unconsciously for the lightning-bolt scar on his own forehead. Had anyone ever used dittany on it? Or was a curse scar completely impervious to any sort of treatment?

He suddenly realized that Snape was staring into Malfoy's gray eyes... Furthermore, the other boy was glaring furiously at Snape, his muscles tensed. Wandless Legilimency, Harry guessed. And Draco's Occlumency was fighting Snape off. Fascinated, Harry watched the battle of wills. How odd to see it from the outside instead of feeling Snape's invading bull charging brutally through the fragile china shop of Harry's own mind.

But suddenly, he was no longer merely an outside observer—Harry was INSIDE Snape, feeling the effort it took the older wizard to try to pierce Draco's Occlumency Shields. Snape's attempts to penetrate beyond Draco's pupils met with a persistent thick fog which flashed different colors as Snape tried various tactics to force his way through the brume. To no avail, as it turned out.

Snape finally withdrew his gaze, leaving Draco to smirk in triumph, and casting Harry back to his former spot by the foot of Draco's bed.

Harry wondered what Snape had been searching for… what he'd failed to find.

"So, what were you after?" challenged Malfoy. "Still trying to figure out how I'm going to—"

"LEGILIMENS!"

Snape's wand had appeared from nowhere, pointing directly at Draco's face, and Harry's nerves practically screamed as he watched Draco struggle against the wanded spell.

Once again, Harry found himself sucked into Snape's mind, feeling every bit of mental strength it took Snape to force his way through the fog that Malfoy produced. A few random flashes of Draco's memories: Quiddich, a screaming woman, the Room of Requirement, Lucius, Voldemort, Harry himself pointing his wand—Snape focused and strained—but the fog closed in again, impenetrable, relentless.

Finally, Snape let go, and Harry felt the man's anger, frustration, and—fear? But then Harry was standing by Draco's bed, out of Snape's mind once again.

Madam Pomfrey had lurched backward, away from the bed, and was staring aghast at Snape. Even so, she wisely kept silent until Snape himself finally dropped his wand arm, ending the spell. Malfoy collapsed against the pillows, gasping and shaking.

"Professor Snape!" protested Madam Pomfrey at last, "Please leave my patient alone! He needs to rest! If he overtaxes his magical core at this stage of recovery, his scars might not heal at all."

Snape sneered silently, and Malfoy managed to pull his salve-blurred features into an expression of defiance.

"Didn't get what you were after, did you, Snape?" the blond youth spat contemptuously.

Harry's jaw dropped. Draco's disrespect toward Snape, first witnessed by Harry during his eavesdropping session immediately following Slughorn's Christmas party, had not abated. If anything, it had deepened. What HAD Snape been after? Malfoy's plans to help Death Eaters into Hogwarts?

"I'll speak to you later—Mr. Malfoy." Snape's voice dripped icicles. "By the way—my compliments to your Aunt Bellatrix. Her tutelage in Occlumency is quite astonishing, given your youth and inexperience."

He whirled in a confusion of ebony wool and had abruptly exited the hospital wing before Harry remembered that he had to follow Snape. The images of Madam Pomfrey and Draco had already begun to fade away as Harry dashed through the hazing doorway. The stone walls regained solidarity around him as he caught up to Snape, although that effort was a feat in itself. Snape was stalking the corridors so rapidly that Harry had to keep running to maintain the integrity of the Pensieve. If he dawdled, he imagined that the Pensieve might just chuck him back out into McGonagall's office, where he'd have to start over again—IF she'd let him.

Harry practically fell flat on his face halfway up the last staircase as he pursued Snape's top-speed ascent back to the boys' bathroom. How LONG were the man's legs anyway? Students scattered before Snape, who was nearly running himself now, his black robes whipping through the passage they'd vacated for him. Harry pounded in his wake, almost beginning to pant with exertion.

Snape stepped into the bathroom and closed the heavy door behind him. Harry blew straight through the solid oak as if it didn't exist just in time to see Moaning Myrtle swoop back into her toilet.

"I didn't mean it to happen," memory-Harry said at once. His voice echoed in the cold, watery space. "I didn't know what that spell did."

But Snape ignored this. "Apparently I underestimated you, Potter," he said quietly. "Who would have thought you knew such Dark Magic? Who taught you that spell?"

Harry cringed with mortification as he watched his memory-self trying to lie his way out of the situation. Lie to SNAPE? The very man who'd spent half his lifetime lying undetected to Voldemort, fooling the world's most evil wizard until the very end of Snape's sad life? How idiotic, to think for a single second that he could have fooled Snape, of ALL people!

Once again, Harry felt himself sucked into Snape's mind, then plunged into his memory-self's mind: seeing The Half-Blood Prince's Advanced Potion Making textbook, all the annotated pages flipping; then felt a burst of mental energy directed into the past, followed by a vision of Slughorn; the book being handed to Harry with a benevolent smile by the other Potions Master, and another given to Ron as they sat at a table in the Potions dungeon…

And then he was standing alone, watching his memory-self staring at Snape again, in the midst of the wrecked, soaked bathroom.

"Bring me your schoolbag," said Snape softly, "and all of your schoolbooks. ALL of them. Bring them to me here. Now!"

Memory-Harry turned at once and splashed out of the bathroom.

Harry watched Snape, who—for a brief moment—seemed to consider using Reparo to fix the damage inflicted upon the Curse-shattered bathroom, then gave it up and staggered to a side wall, extending a trembling hand to lean against it for support. Harry's eyes widened. Snape? Trembling? Why…?

How Dark WAS Sectumsempra anyway?

For some reason, he'd never bothered to wonder how Snape had occupied his time while Harry himself was desperately retrieving his schoolbag, borrowing Ron's Potions text, and hiding his own in the Room of Requirement. Curious, Harry now watched as Snape leaned his shoulder against the wall and buried his face in his hands, breathing deeply, striving for—control? That was the emotion Harry felt most strongly coming from the memory. What was going on?

Suddenly, the bathroom blurred and Harry found himself in an unfamiliar location somewhere in Snape's memory. Turning in a circle, Harry realized that he—no, they—for Snape was here, too—were in a tiny sitting room, which had the feeling of a dark, padded cell. The walls were completely covered in books, most of them bound in old black or brown leather; a threadbare sofa, an old armchair, and a rickety table stood grouped together in a pool of dim light cast by a candle-filled lamp hung from the ceiling. The place had an air of neglect, as though it was not usually inhabited.

But the quick once-over that Harry gave the room faded into the back of his mind as he gazed in shock at its occupants. Snape was facing Harry, and a woman with long, pale blonde hair stood with her back to Harry, seeming to clutch the front of Snape's robes.

"In other words, it doesn't matter to him if Draco is killed!"

Harry recognized her now—Narcissa Malfoy, Draco's mother, wife to Lucius.

"The Dark Lord is very angry," Snape was saying quietly. "He failed to hear the Prophecy. You know as well as I do, Narcissa, that he does not forgive easily."

But as Narcissa crumpled and fell at Snape's feet, sobbing and moaning, Harry's eyes fixed upon the fourth occupant of the oppressive room.

Bellatrix! Sirius' murderer.

Harry's fists clenched as he saw—for the ten thousandth time?—Sirius being knocked backwards by her Curse … falling … falling … gone. Through the Veil. Never to return.

And Snape was WITH her? Where? Surely not Malfoy Manor? Lucius would never set foot in such a … dump.

"You should be proud," said Bellatrix ruthlessly. "If I had sons, I would be glad to give them up to the service of the Dark Lord."

To Harry's astonishment, Snape lifted Narcissa to her feet and helped her to the sofa, giving her a glass of red wine. Surprising him further was Snape's offer to help Draco. And then—shockingly, although Harry realized he should have seen it coming—the Unbreakable Vow.

Harry watched the magical bonding twining like burning wire around Snape's and Narcissa's clasped hands, as Snape Vowed to watch over Draco, protect him from harm, and—if necessary—carry out the deed that the Dark Lord had ordered Draco to perform—killing Dumbledore, Harry now knew. Dumbledore, already mortally wounded due to the Cursed ring Horcrux; Dumbledore, who had already extracted Snape's promise to end his life to save Draco's soul. Snape could actually make the Vow with Narcissa, although Harry knew from the other memories Snape had relinquished in the Shrieking Shack that Snape hoped it would not be necessary for him to fulfill his promise to kill Dumbledore in the end.

Harry watched as a third tongue of Flame shot from Bellatrix's wand, twisted with the others, and bound itself thickly around the clasped hands, like a rope, like a fiery snake.

Then, he and Snape were back in the boys' bathroom.

Why, Harry wondered, would Snape be thinking about killing Dumbledore while he waited for Harry to return with his schoolbooks? Naturally, it would weigh heavily on Snape's mind—but this setting, these circumstances, made it seem so … improbable.

Before he could ponder it further, his memory-self returned to the bathroom, gasping frantically for breath, schoolbag in hand. Harry watched the second round of interrogation…

"Then why," Snape was asking, "does it have the name 'Roonil Wazlib' written inside the front cover?"

Memory-Harry blanched. "That's my nickname," he said.

"Your nickname," repeated Snape.

"Yeah … that's what my friends call me," said memory-Harry.

"I understand what a nickname is," said Snape, and suddenly Harry felt himself sucked yet again into Snape's mind, his gaze penetrating the panicked emerald eyes of his memory-self.

Harry saw himself in THIS bathroom, before it was wrecked, watching in shock as Malfoy cried into the washbasin. Malfoy looked up into the cracked mirror and saw memory-Harry staring at him over his shoulder.

This? THIS is what Snape was looking for when he'd Legilimized Harry the second time? Harry felt stunned. Why hadn't Snape just asked him how the fight happened? Harry would have told him the truth. Draco had attacked Harry, and Harry had defended himself, eventually using Sectumsempra. That's how the fight ended.

And then, it hit Harry. He'd already lied to Snape. Lied about the source of Sectumsempra. Lied that Ron's book was his. Snape KNEW he'd lied. So why give him another chance to lie, when Harry's mind—unlike Draco's—was the proverbial open book? Carefully-finessed Legilimency would show Snape everything … every last detail.

The bathroom duel played out again before him as Harry considered something else. Draco had also lied, intimating that Harry could have gone into the boys' bathroom hoping to molest a younger male student. Draco had then used Occlumency to keep Snape from getting any further information. Was THIS what Snape had wanted to see? The fight itself? Not Draco's plans to get Death Eaters into Hogwarts as Draco's angry query to Snape had seemed to indicate?

In his own mind's eye, Harry saw it again, that moment in the hospital wing—a split-second flash of himself in Draco's memory: Harry pointing a wand. Wasn't that when Snape had focused and strained? Yes! But Draco had pushed him out before he could extract any information beyond a glimpse. Harry himself hadn't paid attention to any details; it could have been him in this bathroom, or it just as easily could have been him at Lockhart's dueling club in second year. Snape would have known the difference, though.

Now, while Snape Legilimized his memory-self, water poured everywhere and memory-Harry slipped as Malfoy, his face contorted, cried, "Cruci—"

"SECTUMSEMPRA!" bellowed memory-Harry from the floor, waving his wand wildly.

Blood spurted from Malfoy's face and chest…

Memory-Harry fell to his knees beside fallen Malfoy…

The door banged open behind memory-Harry and he looked up, terrified. Snape had burst into the room, his face livid—

Suddenly, Harry was standing back in the Pensieve bathroom beside his memory-self and Snape, the second round of Legilimency over.

"Do you know what I think, Potter?" said Snape, very quietly. "I think that you are a liar and a cheat and that you deserve detention with me every Saturday until the end of term. What do you think, Potter?"

"I—I don't agree, sir," said memory-Harry, now refusing to look into Snape's eyes.

The scene in the Pensieve suddenly shifted away from the bathroom, momentarily disorienting Harry. Now he and Snape were in Dumbledore's office. Dumbledore sat gravely at his desk, watching Snape's severe profile as the dark-haired man looked out the tower window, squinting at the sunlight reflecting from the surface of the Black Lake.

"That damnable Vow," muttered Snape. "I never should have made it."

"You could not have known, Severus."

Snape turned from the window to face Dumbledore fully. "But I should have guessed that the possibility existed. In Draco's frame of mind—his father in prison—the illustrious Malfoy family name tainted because Lucius failed to retrieve the Prophecy—and myself suddenly being asked to sit at the Dark Lord's right hand, which had been Lucius' seat for years, even before Draco was born…"

Snape shook his head, clasping his hands tightly. "If only Narcissa had been wise enough to hold her tongue concerning the Vow."

"But she told Draco," Dumbledore surmised.

"I suppose she'd hoped to share her sense of relief with her son … relief that he would have an ally as he worked to fulfill his mission … a failsafe …" Snape's voice trailed off. Then his expression hardened. "I failed to take into account the possibility that Draco would repeatedly attempt to turn the Vow against me, thereby to effect his revenge through my resultant demise."

Harry gaped at Snape's statement. Draco had tried to use the Unbreakable Vow itself to get Snape killed? Snape, who had Vowed to PROTECT Draco?!

"When did you first suspect his actions?

"Slughorn's Christmas party," Snape replied. "Several minor incidents prior to that had made

me wonder, but his crashing of the party, then seeming disappointed when he was permitted to stay and did not receive any punishment … that's when I knew for certain."

"Ah, yes," said Dumbledore. "As I recall, you took young Mr. Malfoy out of the party and gave him a serious talking-to, but he seemed disinclined to heed your warnings."

Snape smiled grimly. "When I brought up the Vow, he wasn't the least surprised to hear about it, and even told me I'd just have to break it."

"I remember your telling me," said Dumbledore softly. "How very callous of Draco. However, Draco's attempts to turn the Vow against you fit into his general 'modus operandi'—he did not possess the courage to attempt to kill you face to face, any more than he could kill me directly. Like the Vow, the Cursed necklace and poisoned mead were merely other means of his indirect attempts to have someone killed, rather than boldly committing murder with his own hands."

"Tell me something I don't already know," Snape responded sardonically.

The two men fell silent for several contemplative moments. Dumbledore studied his steepled, gnarled fingers, while Snape stared at the rhythmically-rippling waters of the lake. Finally, Dumbledore broke the long silence.

"And today, Severus?"

Snape glowered at the Headmaster. "Draco Malfoy attempted to cast an Unforgivable against another student."

"Harry Potter."

"I—How did you already know…? It's only just happened… I came here straightaway after dealing with Potter."

Dumbledore chuckled amiably. "Moaning Myrtle popped up in my private bathroom mere moments after the duel, regaling me with a tale that murder had just been committed in a boys' bathroom. She happily informed me that Harry had cut Draco to ribbons, and I happily informed her that if she wished to remain in residence at Hogwarts, she would not invade my personal chambers again. She screamed and dove back into the toilet."

Harry snickered, visualizing the impromptu encounter between the jovial Headmaster and the wailing ghost of a former female student.

Dumbledore smiled benignly. "I'd been waiting for you to show up."

Snape looked nonplussed for a moment, but he quickly regathered his thoughts.

"Headmaster, if Draco had succeeded in casting an Unforgivable, what would you have done?"

Dumbledore looked at Snape over his half-moon spectacles. "Which Unforgivable, Severus?"

"Crucio."

"Do you believe Draco could have cast it successfully? He's only sixteen."

"I've seen him do it," Snape stated flatly. "Lucius began training him two years ago. Draco can cast all three Unforgivables."

"Even Avada Kedavra?"

"Thus far, he's killed only animals. That I know of," Snape added, his lips twisting unpleasantly. "The largest was a—doe."

Harry felt queasy—the significance of the doe did not escape him.

"I see."

Dumbledore rose from his chair and strolled to the window which Snape had been gazing through. "In answer to your question, I would have had no choice, Severus. Draco's Unforgivable would have forced me to expel him."

Snape stared at his mentor. "Even knowing that—"

"Yes, Severus. Even knowing that Draco's expulsion would nullify his chances to complete the mission that Voldemort had given him. Even knowing that said expulsion would seal your death warrant by means of the Unbreakable Vow."

Harry felt his fists ball up at the Headmaster's traitorous admission. Dumbledore would throw Snape—LOYAL SNAPE—aside? Let him DIE?! Never mind that Snape could be a git—Dumbledore couldn't just LET Snape DIE! Harry felt absolutely nauseous with horrified fury.

Dumbledore turned to face the younger wizard frozen a few paces away. "I would not have been able to save Draco from the Aurors—you know that. The Ministry would have detected an Unforgivable, and given that Alastor Moody's rather eccentric teaching practices are not registered with the Ministry for this term at Hogwarts, the Aurors would have descended upon the castle within seconds. Harry's screams would still have been echoing in the corridors when Draco was arrested and taken away to Azkaban. Even without expulsion, his arrest and imprisonment would have been sufficient grounds for the Vow to take effect. There would have been no stopping it, Severus. To my very deepest regret."

After a long, heart-stopping silence, Snape gave the tiniest of nods, and Harry felt the man's sense of angry defeat at the inescapability of the situation which had very nearly killed him today. Also, an unrelenting, angry fear at the knowledge that Draco might STILL manage to achieve that same end, through some as-yet-unforeseen rash action.

Dumbledore closed his eyes. "Was Draco's Unforgivable another stab at you?"

"No," said Snape, beginning to pace back and forth across the small floorspace of the office. "He was angry at Potter and attacked him—without provocation on Potter's part, as far as I could tell. Although…" Snape paused, deep in thought, "… perhaps, subconsciously, he may have hoped his actions would turn the Vow against me."

"But you stopped him in time," Dumbledore smiled. "And we live to fight again another day."

"I did not stop him."

"Oh?"

Snape's smirk was decidedly off balance.

"Potter—stopped him."

Dumbledore's eyebrows rose. "Harry disarmed him?"

Snape pinched the bridge of his nose. "Not … exactly." He looked Dumbledore in the eye. "For once, Moaning Myrtle's report was accurately factual. Potter cut Draco to ribbons."

Dumbledore's mouth opened, but it was a moment before he got the word out. "How?"

"Sectumsempra."

"Gracious!"

Snape sighed heavily. "Horace Slughorn apparently loaned Potter my old Potions textbook, presumably at the beginning of September. By Christmas, Potter had established an undeserved reputation for brewing excellence which far surpassed even that of Miss Granger." Snape rolled his eyes in irritation. "My book not only contained numerous annotations for improving upon the standard Ministry-approved Potions, it also held various spells and curses of my own invention, Sectumsempra among them."

"I see," murmured Dumbledore. "And young Harry decided to experiment on Mr. Malfoy? I should have a word with him."

"It was self-defense," blurted Snape before he stopped to think that he was DEFENDING Potter. POTTER!

Harry could see his discomfiture and grinned appreciatively. This was certainly one for the books!

"Draco started to cast the Cruciatus Curse, and Potter countered with Sectumsempra."

Dumbledore's blue eyes peered intently at Snape. "How far did Draco get?"

Snape took a deep breath. "He was one syllable away from causing my death."

Dumbledore's exhalation hissed between his teeth.

"So … Harry saved your life."

Utterly stunned at Dumbledore's abrupt pronouncement, Harry nearly fell over.

Snape's thin lips twisted. "Unwittingly," he admitted. "Potter is not aware of that fact." He reached out, hesitated, then grasped Dumbledore's arm. "Headmaster, I don't want him to know. He CANNOT know. Not now. Not ever."

Dumbledore looked thoughtfully at the arm Snape was still holding.

"You said you'd 'dealt' with Harry. How, might I ask?"

Snape dropped his hand, freeing Dumbledore.

"Thirteen Saturdays of detention," he said baldly.

"Severus!" Dumbledore stared at the younger wizard askance. "A baker's dozen of detentions for saving your life? Really!" He sounded quite scandalized at the very idea.

"No," corrected Snape . "Thirteen detentions for being a liar and a cheat." When Dumbledore appeared ready to interrupt, Snape continued, "I was very specific, Headmaster. The detentions are strictly for lying and cheating—nothing else. I told Potter exactly so—that I believed him to be a liar and a cheat."

That was actually true, Harry realized with sudden blinding insight. How had he missed it at the time? When Snape assigned all those Saturday detentions, he had NEVER ONCE said a single word about punishing him for using Sectumsempra or nearly killing a fellow student. But it had certainly FELT as though he'd been punished for it. Because, Harry also realized at long last, he had been EXPECTING to be punished for Sectumsempra. Anyway, even McGonagall had said afterwards that he'd been lucky not to have been expelled. After all those years where Snape had kept threatening to have him expelled for relatively minor infractions, when Harry finally committed a HUGE atrocity, thereby handing Snape the golden means on a silver platter to expel him, all Snape did was assign Harry a bunch of detentions.

Harry mentally kicked himself. He should have KNOWN something was up!

But at that moment in time, all he'd been able to see was the image of Draco Malfoy shaking uncontrollably in a pool of his own blood superimposed over Saturday after Saturday after Saturday… Yes, he'd expected punishment, and when it came, he never stopped to analyze it. Snape was masterful, he had to admit.

Suddenly, Harry realized something else. Perhaps a year on the run, living rough and everything else he'd experienced while hunting down the Horcruxes, had somehow helped to enhance his understanding. Snape had HAD to punish him severely, because the offense against Draco required it. But what an awkward situation for Snape to find himself caught in: he was FORCED to mete out punishment proportionate to the severity of the offense, even though that same offense had saved Snape's life. Not to mention, he also had to acknowledge a wizard's life debt in the process. Snape had managed to do it, by specifying—however obliquely—that the detentions were strictly for lying and cheating. Never mind that the specifications had gone completely over Harry's head. Undoubtedly, Harry's lack of comprehension was exactly what Snape had intended via the roundabout acknowledgment!

Harry had to shake his head in reluctant admiration. Snape had really pulled the wool over his eyes that time. DAMN, but the man was clever!

Dumbledore was still staring at Snape.

"Severus…" he said slowly.

"It was the best I could manage on short notice," Snape defended himself. "And Potter CANNOT know, Headmaster."

Dumbledore waited a very long moment before finally inclining his head. "I shall respect your wishes, Severus. But I hope—for both your sakes—that one day you might reconsider. Harry might be interested in knowing that he had repaid one of his own life debts to you."

Snape quirked a brow. "I'll take that under advisement."

Dumbledore's eyes began to twinkle.

"Tea, Severus?"

Snape smirked. "Quite honestly, Headmaster, today I could do with something a bit stronger."

As Dumbledore chuckled, the office view whirled around Harry, and he landed awkwardly on the richly-patterned rug beside Minerva McGonagall's desk.

"Well?" asked the Headmistress, her eyebrows raised high in curiosity.

Harry held up a finger, signaling for a moment to marshal his thoughts. Something was just escaping him… He closed his eyes, thinking hard.

Sectumsempra.

When the memory first opened, Harry had chastised himself for having cast an unknown Curse, wishing he'd turned the book in to Slughorn before he'd ever seen "Sectumsempra—For Enemies" scribbled on a page deep within the text.

And yet…

And yet … if Harry had NOT cast Sectumsempra, Snape would have died because of the Vow. Harry would never have seen Snape's memories. Harry might never have had the information he needed to face Voldemort in the manner that he eventually had. He might have fought to win, never knowing that he needed to sacrifice himself instead. By this time, Voldemort—not McGonagall—might be sitting behind the Headmaster's desk at Hogwarts.

Harry shuddered.

Sectumsempra had made all the difference.

He thought back to that final, lone memory creeping down the side of Snape's cheek. Harry would bet anything that it had been the Sectumsempra memory. Not necessary to the defeat of Voldemort, but—an acknowledgment. Snape's final act.

A sudden "POP" was followed by a house elf's voice.

"Where do you wish it, Headmistress?"

"Up there will be fine," said McGonagall, pointing to the wall across the office from her ornately-carved desk. "Albus said he wanted it placed directly opposite his own."

Harry finally opened his eyes and turned to see what the house elf—elves, actually, since there were two of them—had brought.

After carefully removing a velvet covering, the elves quickly levitated a framed portrait to the empty spot on the wall. After sticking it securely into place, the elves bowed and popped away, taking the velvet with them.

Harry watched Minerva McGonagall point her wand at the portrait.

"Ennervate!"

Severus Snape breathed deeply, stretched, worked a crick out of his neck, and cast a black glance at his surroundings. Realization seemed to hit him hard.

"Dear Merlin!" Snape whispered. "It really wasn't just a nightmare…"

McGonagall regarded him sympathetically. "I'm afraid not, Severus." She swallowed hard. "Severus, may I please ask you to forgive me? For trying to kill you, that is… I truly did not understand your situation."

Just as Snape was about to reply, he spotted Harry standing near the Pensieve. "Potter!" I must tell you—there are things you need to know—I tried to give you my memories—"

"It's okay, sir," said Harry, coming forward toward the portrait. "You did give me your memories, and I saw them—all of them. The Final Battle is all over now. Voldemort is definitely dead, I survived the Killing Curse again, and Hogwarts is still standing. Welcome home, sir!"

Snape glared suspiciously at Harry, not inclined to blindly accept his word that all was indeed well, until McGonagall caught his eye, nodding affirmatively.

"We lost a number of good people, Severus. They gave their lives to gain our victory in the end. But most importantly, you helped Potter defeat V-Voldemort," she smiled, her lips trembling slightly. "He's never coming back." Very softly, she added, "Thank you, Severus. For all you've done for the Side of Light through the years."

Snape solemnly acknowledged her gratitude before looking at Harry again. "And are you—all right—Potter?"

Harry nodded. "The fragment of Voldemort's soul that was within me has been destroyed. I am no longer a Horcrux."

"Nagini?" Snape asked, reflexively probing at the black fabric over his throat.

"Neville beheaded her."

"Longbottom!"

"With the sword of Gryffindor, I might add," said a voice from across the room. Dumbledore had awakened in his own portrait and lost no time making extended eye contact with Snape.

Legilimency? Between PORTRAITS? Harry gaped in wonderment.

Snape finally leaned back in what appeared to be a comfortable leather armchair. "It would seem that we have much to discuss, Potter." He waved a dismissive hand. "At a later date."

Harry nodded. "Yes, sir. And Professor?"

Snape looked down at him. The painted obsidian eyes seemed almost to be twin holes through the canvas itself. "Yes, Potter?"

"Thanks for the memories. All of them. Including Sectumsempra."

After a moment, Snape gave a jerky nod. "You're welcome."

Harry himself nodded, first to McGonagall, then to Dumbledore, and finally to Snape. "I'll just be going now. But I'll be around. I'm planning to come back for my final year at Hogwarts." He grinned and turned, waving a casual farewell to the office's sundry occupants in general.

As Harry headed for the moving spiral staircase to exit the Headmistress' office, Severus Snape found himself smiling slightly at the young man's back.

He followed up the smile with an anticipatory smirk.