When the emerald tongues of flame died down, Harry turned back to Dumbledore, Snape, McGonagall, and Pettigrew. Snape had fixed Pettigrew with a murderous glare.

“This—” Snape jerked his head toward the shabby man-bat, “explains quite a bit.” Pettigrew flinched away from Snape’s vehemence. Harry could hear Dumbledore sigh softly behind him.

“It would certainly seem so, Severus,” Dumbledore agreed. McGonagall looked between her colleagues shrewdly.

“But Severus—” she began, “Peter has been alive all this time…Why weren’t you able to feel his presence?” Snape shook his head slowly, crossing his long arms over his chest to grasp the folds of his outer robes. He was clenching them so hard that his knuckles were turning white, standing out painfully even against his pale skin.

“You must understand Minerva, at the time…when I was—Well, I—we—never completed the Bond,” he sneered at Pettigrew with sheer malice. “With our mutual…enmity…Well, suffice it to say neither party wanted anything to do with the other.”

What on earth is Snape on about? Harry thought. Never completed the Bond? What— He gasped sharply and looked up at Snape. His throat felt dry.

“So,” Harry said, clearing his throat and feeling immensely awkward, “Sca—er, Pettigrew is, er, a vampire? And he bit me…and…” Harry gulped, trailing off. The three professors looked at him like they’d just remembered that he was there, still sitting in the spindly black chair in front of Snape’s desk. Harry’s face flushed and he lowered his gaze to his lap.

“Ah,” Dumbledore started, making the ropes of light that bound Pettigrew flare brightly for a moment, “I do believe an explanation is in order, Harry.” Harry lifted his head and met Dumbledore’s twinkling blue stare.

“You may not have known this,” Dumbledore said, “but Professor Snape was in your father’s year at school—”

“Really?” Harry leaned forward, his interest
piqued. Snape scoffed from behind his desk, his arms still arranged resolutely across his chest. Dumbledore sent him a reproving look, but Snape’s scowl only deepened.

Dumbledore did tell me last year that my father saved Snape’s life once; I knew they must have at least known each other… Harry mused.

“I just—I didn’t know they were the same age.” Harry said aloud. He chanced a cursory glance at Snape, but when onyx eyes bored back, he flinched away.

Gah! How does he do that? Harry ruminated. It’s like he burns people just by looking at them!

Noticing the exchange, Dumbledore allowed himself a small smile.

“Yes, Harry,” Dumbledore replied gently. “Your father was in Gryffindor, and he had a group of close friends in his house.” McGonagall nodded. She had a faraway look on her face.

“James Potter, Sirius Black, Remus Lupin, and Peter Pettigrew,” She practically spat the last name, changing her demeanor dramatically and staring down the subject of her derision like a lioness about to pounce on her prey. “They were thick as thieves during their years here.”

Snape snarled at this, releasing his death grip on his robes to pound his fists into his desk. Harry jumped in his seat, startled by Snape’s outburst. Pettigrew let out a nervous wimper.

“Get. To. The point,” Snape ground out through clenched teeth. Harry noticed that both Dumbledore and McGonagall were frozen in place with funny expressions. “I’ll tell the boy if you two won’t—or shall I have Pettigrew explain?” Snape snatched up a phial of Veritaserum and glared menacingly at the uncharacteristically hesitant Gryffindors. Pettigrew cowered in the ropes. Harry frowned to himself, puzzled.

I’ve never seen Dumbledore or McGonagall looking this cowed, he observed.

“Severus…” Dumbledore murmured, looking strangely apologetic.

“Don’t, Albus!” Snape hissed, his voice pitching dangerously low. “Go on, tell the boy how his sainted father and his friends very nearly murdered me in our Fifth Year. But—don’t leave anything out…unless you want me to fill in the details for you…” Snape let his threat trail off, leaving his accusations hanging in the air.

“That’s not true!” Harry burst out indignantly. “Professor Dumbledore told me last term that my father saved your life!” Snape rounded on him, his robes and hair whipping about.

“Tell me Potter,” he spat, “can it really be considered a rescue if your father simply got cold feet when his friends designed a prank to kill me?” Harry shrank back in the chair. His confusion must have been plain to see because Snape went on. “That’s right, Potter! Your father and his friends proved they were capable of murder at sixteen! I’d noticed they all seemed to disappear every full moon, and I had reason to suspect that they were…up to no good. Black tricked me into following them one month, and I was attacked by a werewolf and a vampire—Lupin and Pettigrew. Your father managed to drag me back to the school before I bled out, but not before…I was bitten.” Snape finished his tirade with a fierce scowl, his black eyes flashing and his chest heaving in anger. Shaken, Harry’s gaze left Snape and focused on McGonagall and Dumbledore. From the defeated slouch of Dumbledore’s shoulders to McGonagall’s downcast face, Harry sensed Snape was telling the truth.

“So…you’re—” Harry faltered. Snape nodded curtly.

“It takes one to know one, Potter,” he bit out.

Harry blanched.

Touché, Snape, he thought wryly.

“During my final two years at Hogwarts, I was overcome with bloodlust. In order to avoid biting my schoolmates, I subsisted on animal blood—creatures in the Forbidden Forest. For my Potions Mastery, I –among other...efforts—devised a potion that acts as an alternative to human—and animal—blood. I’ve lived off it ever since. With the potion, I’ve no need of a Blood Bond,” Snape said, some of his anger leaving his voice. Harry’s eyes widened in understanding.

That’s bloody ingenious! Harry marveled to himself.

“Then…that’s the potion I took earlier, right? Sir?” he asked. Snape just smirked. But Harry’s curiosity wasn’t fully satisfied.

Looking to Dumbledore, Harry said, “Professor, if—if my father and his friends…er, nearly killed Professor Snape—and turned him…er, were they expelled or something, then?” After all, Harry and Ron had nearly been expelled a few hours ago for crashing a car into the Whomping Willow. And damaging a tree wasn’t nearly as bad as injuring a person!

Dumbledore shifted from one foot to the other, looking quite unnerved. Snape glanced at Harry out of the corners of his eyes with a carefully neutral mien. Everyone was silent for a moment. The only sound that could be heard was Pettigrew’s wheezing against his bonds. Finally, Snape snorted.

“See? Even Potter agrees with me,” he snipped, sneering at Dumbledore and McGonagall. Dumbledore’s normally warm and welcoming persona turned slightly chilly.

“Shall we return to the matter at hand?” he suggested pointedly. McGonagall pursed her lips but nodded assent. Snape huffed, shrugging his indifference. He uncorked the Veritaserum and approached Pettigrew with a feral gleam in his eyes. Pettigrew cringed away as Snape drew near, but he was helpless as Snape grabbed his throat and lower jaw and wrenched his mouth open.

“Vengeance is sweet,” Snape snarled, tightening his claw-like grip on Pettigrew’s chin.

Harry watched with equal parts revulsion and fascination.

Snape sure is strong! I wonder if that’s a vampire thing or— His thoughts were interrupted by Pettigrew’s squawk of protest.

“No! Severus! Please—” Pettigrew cried. Snape merely sneered, forcing the Veritaserum into Pettigrew’s mouth. After a few tense seconds, Pettigrew began shuddering in his ropes of light. Dumbledore grunted and strengthened his casting. Pettigrew’s eyes rolled up in his head, and his head lolled on his chest. Harry shifted as far away from the stubby man as he could.

“Who was the Potters’ Secret Keeper?” Snape asked.

Secret Keeper? Harry wondered.

Pettigrew gave another shudder, and he answered tonelessly, “I was. Sirius convinced James to change it to me at the last minute.” Harry thought it was rather disconcerting to watch, really. Snape’s nostrils flared as he digested the new information.

“Why?” The question came from McGonagall this time.

“He believed I was the one that Death Eaters least expected to be the Secret Keeper, so the Potters’ location would be safest with me,” Pettigrew explained in monotone.

“Did you betray the Potters to the Dark Lord?” Snape probed.

Pettigrew shook again, but he said, “Yes.” Dumbledore and McGonagall exchanged significant glances.

“Who killed the muggles during your confrontation with Sirius?” McGonagall demanded.

“I did. And then I faked my own death,” Pettigrew smiled. With only the whites of his eyes visible, and his chin tilting listlessly on his chest, Pettigrew looked like a marionette whose strings had been cut. Harry worked hard to suppress a shudder of his own.

“I think we’ve heard enough,” Dumbledore said. Snape nodded grimly. McGonagall moved to stand behind Harry where he was sitting, and she placed a comforting hand on his shoulder.

“May I use your Floo, Severus?” Dumbledore inquired.

“Of course, Headmaster,” Snape said stiffly. He still hadn’t gotten over his anger.

Snape can sure hold a grudge, thought Harry. He wasn’t ready to think about the things Pettigrew had said under Veritaserum just yet. He didn’t want to. Nor did he understand it all.

Dumbledore strode over to Snape’s fireplace and grabbed a handful of powder from the jar on the mantle. He swept it into the fire, crouching down to stick his head in the green flames.

“Amelia Bones, Department of Magical Law Enforcement, Ministry of Magic,” he called out.

“Albus!” a woman’s voice exclaimed from the flames.

“Amelia,” Dumbledore began gravely, “I request permission to come through at once. Ready a unit of Aurors and a Pensieve if you would, please. I have incontrovertible evidence that Sirius Black has been wrongfully imprisoned.”

“Black?” the other witch repeated faintly, the skepticism evident in her voice. “Innocent?” Snape muttered something under his breath that Harry knew he’d get a week’s worth of detentions for repeating.

“Yes,” Dumbledore said firmly, tightening his hold on his wand. The ropes of light around Pettigrew constricted briefly.

“Well, come on through, then!” Amelia Bones recovered.

Dumbledore pulled his head out of the fireplace and took one last glance around Snape’s office, nodding to himself. Pettigrew was still slumped in his bonds—it seemed Snape had been a little overzealous when he’d dosed the captive with the Veritaserum.

“Minerva, please come with me,” Dumbledore said, reeling the listless Pettigrew closer to the fireplace. “Severus…please explain to Harry…” Dumbledore trailed off. McGonagall looked between Snape and Harry, then nodded to Dumbledore. She grasped Harry’s shoulder gently once more, then took some Floo powder for herself.

Throwing it on the flames, she said, “Department of Magical Law Enforcement, Ministry of Magic.” Dumbledore got a firm hold on one of Pettigrew’s ears, then followed after Minerva.

Watching them leave, Harry turned nervously back to the dour Potions Master.

“Er, Professor?” Harry tried. Snape raised an eyebrow. Harry took it as a sign of acknowledgement and continued.

“What’s a Secret Keeper, Sir?” he asked.

Snape frowned. He seemed to be considering Harry’s question, at least.

“A Secret Keeper,” he said at last, “is one component—the main component—of the Fidelius Charm.”

“What’s the—” Harry started, but Snape had already begun to answer his next question.

“The Fidelius Charm is an extremely ancient, multifaceted, and potent charm that can be used to conceal a secret inside an individual's soul; the witch or wizard who houses the secret is known as the Secret Keeper. A dwelling whose location has been protected by this spell is then invisible, intangible, unplottable and soundproof. The information hidden inside the Secret Keeper is henceforth impossible to find—unless, of course, the Secret Keeper chooses to divulge it,” Snape lectured. “As long as the Secret Keeper—Pettigrew, it seems—refused to speak, the Dark Lord could’ve searched where your family was staying for years and never would’ve found them.”

Harry blinked rapidly, his thoughts and emotions hacking their way through the thicket of new knowledge.

“D’you mean that bat is the reason my parents are dead? He betrayed his friends! He sold my family to Voldemort! I hate him! I hate him!” Harry shook with rage. He was clutching the arms of the chair with such force that his nails were gouging the wood. For a few seconds, Harry’s harsh breathing was the only sound in the dark, cramped dungeon office.

Snape remained emotionless during Harry’s outburst. “Do you really think Pettigrew is the only person to blame for your parents’ deaths, Potter?” he asked tonelessly. Harry peered up at him, taking deep breaths to reign in his anger. Snape’s face was an expressionless mask. Harry watched Snape slowly trace his long forefinger up and down the inside of his left forearm.

“No…” Harry admitted reluctantly, “Voldemort was the one who said the curses, I know that. It’s just—from the way you talked—it sounded like Pettigrew was supposed to be their friend…and he betrayed them…he betrayed them all…”

Snape nodded, but Harry sensed his mind was elsewhere.

Deciding they both needed a subject change, Harry asked, “Professor, what’s a Blood Bond?”

Snape’s eyes snapped back into focus; he’d returned from whatever place his mind had taken him. His lip curled, but he wasn’t quite sneering at Harry, at least not completely.

“Why do you want to know?” Snape inquired.

Harry shrugged one shoulder.

“Just curious. Sir.”

Snape let out a breath and steepled his hands together, his elbows resting on stacks of paper on his desk. His lank hair swung past his collar as he leaned forward.

“How much do you know about vampires, Potter?” Snape began carefully.

Harry frowned in thought.

“Well not much, Sir. Professor Quirrell was an awful Defense Against the Dark Arts teacher even before I realized he was carrying Voldemort around on the back of his head!” he said. Snape winced.

“Yes…” Snape agreed. “But the incompetence of your possessed professor notwithstanding, it would be in your best interest to learn as much as you can about vampires.”

Harry nodded. “Considering I am one, now, right?”

Snape smirked. “Indeed.”

“So…Blood Bonds…” Harry prompted. Snape pinched the bridge of his nose and glanced up at the gray stone ceiling.

“Very well,” he sighed. Harry tried and failed to conceal his own smirk.