The Hogwarts Library was a cathedral of knowledge, its towering shelves reaching up into the arched, shadowed ceilings, illuminated only by the faint, dust-moted beams of moonlight filtering through the high windows. The air was thick with the scent of aged parchment, dry leather, and a faint, indefinable magical stillness that discouraged sudden movement or loud noise. It was a perfect setting for the most torturous of detentions.
Three figures—James Potter, Sirius Black, and Peter Pettigrew—were positioned at the end of Aisle 7, a section dedicated primarily to Ancient Runes and obscure legal texts. They were dressed in their usual school robes but covered in a fine layer of dust, looking utterly miserable. They were following the tedious instructions of Madam Irma Pince: cataloging, categorizing, and dusting every volume on the shelf.
James Potter, the self-proclaimed leader of the trio, was attempting to balance a thick, rune-covered tome while simultaneously running a damp rag over the shelf beneath it. His efforts were clearly hampered by a series of crisscrossing, scabbing scratch marks across his left cheek and forehead—the painful, lingering result of the kneazles' protective frenzy at the Yule Ball. He kept wincing whenever he stretched the skin near his jaw.
"I still maintain," James muttered under his breath, carefully setting the book down, "that the punishment is disproportionate to the crime. It was a jam tart, Sirius. A jam tart. Not a strategic assault on the Head Table."
Sirius, who was meticulously sorting a pile of identically sized books, shrugged, a dark, dusty smudge highlighting the prominent bone structure of his face. "You threw it at Snivellus. The whole point was to get noticed by Eveans. You got noticed, but instead it was Dumbledore and McGonagall. You're lucky we didn't end up scrubbing the troll bogeys out of the Transfiguration classroom."
Peter, who was responsible for the dusting, simply sniffled and continued to swipe his rag aimlessly.
Madam Pince, the guardian of the sacred volumes, stood over them like a silent, implacable sentinel, her arms crossed tightly over her chest, her face a mask of severe displeasure. She wore a thick, woolen shawl despite the mild temperature, and her sharp, bird-like eyes missed nothing. She had spent the last hour simply watching them, her presence an oppressive weight.
Finally, she broke the silence, her voice a low, dry rasp. "You three. Your categorization of the 'Runes of the Caucasus' section is wholly unacceptable. These three volumes are arranged by publication date, not by the height of the bindings. The bindings are merely cosmetic. You treat these repositories of knowledge as if they were mere… paperweights." She spat the final word out like a curse.
"Sorry, Madam Pince," James said quickly, flexing his scratched jaw. "Won't happen again. We'll re-sort immediately."
Madam Pince looked at him, her gaze lingering on the angry red marks across his face. "Indeed. Well. I must retrieve the trolley from Aisle 47 to transport these misaligned volumes to their correct storage location. You will remain here. You will continue precisely as you were. And you will not cause any disruption. Do you understand?"
The three Marauders exchanged a quick, weary glance. "Yes, Madam Pince," they chorused dutifully.
Madam Pince gave a curt nod of satisfaction, turning her back on the penitents. She began her long, silent walk down the main aisle, her footsteps making no sound on the ancient stone floor. As she reached the far end of the library, the dark, massive outline of the heavy brass trolley was just visible in the gloom. She reached out, placing both hands on the cool metal, and prepared to push the cumbersome thing back toward the detention zone.
"Good evening, Madam Pince." The soft, simple phrase, spoken in a cheerful, conversational tone, came from directly behind her.
Madam Pince let out a gasp that was entirely muffled by surprise, and her head snapped around with the speed of an angry clockwork puppet. Her eyes, wide with shock, found the source of the voice. Echo was standing less than a foot behind her. He was dressed in clean, dark robes, his hair a placid, innocent gray, and he was smiling a sweet, disarming smile. He looked as if he had simply materialized from the shadows of the bookshelves.
"Oh! Dear me, I do apologize, Madam Pince!" Echo said, his voice dropping immediately into a tone of earnest concern. "I am so terribly sorry! I didn't mean to startle you. I'm afraid my habit of walking silently—you know, to avoid disturbing people—isn't always helpful when approaching people from behind. I must remember to tap my foot or something."
Madam Pince was still recovering, one hand clutched to her chest. "Mr. Echo!" she finally managed, her voice a reedy whisper of indignation. "What in the world are you doing here? The library is closed, and it is well past curfew!"
Echo's smile remained fixed and entirely genuine. "I know, Madam Pince. I just finished my own… well, let's call it an extended commitment. And as I was heading back to the common room, I realized I had to stop and correct a profound oversight."
He stepped closer, his gaze sweeping over the towering, silent shelves with an expression of deep respect. The neutral gray in his hair softened to a quiet, deep lilac—a shade of profound thoughtfulness.
"I simply wanted to thank you, Madam Pince," Echo said, his voice dropping to a conspiratorial, sincere murmur. "For your hard work. Your dedication to this institution and to the very idea of knowledge."
Madam Pince blinked, completely taken aback. She had been prepared for anything—a complaint, a bribe, a poorly executed prank—but not this.
"And for your proper respect for these books," Echo continued, gesturing to the shelves around them. "And their safety. It must be so incredibly difficult to have a job where almost everyone who enters this place treats these books as mere objects, as paperweights, or as disposable sources for last-minute research. But you see them for what they are: the knowledge, the magic, locked in the pages inside. And you protect it fiercely." He sighed, his gaze returning to her. "I imagine it must feel utterly thankless, but I want you to know that some of us see it. And we respect it. Thank you, Madam Pince. Truly."
Madam Pince's severe expression dissolved into one of profound, utter confusion. Her sharp eyes, usually so calculating and judgmental, darted around the shelves as if seeking confirmation that the boy speaking to her was, in fact, Echo. The lilac in Echo's hair deepened, lending an air of deep spiritual reverence to his simple declaration.
"I… I do not know what to say, Mr. Echo," Madam Pince finally managed, her voice a weak, cracked whisper, entirely devoid of its usual authority. "T-thank you. That is… entirely unexpected."
Echo waved a dismissive hand, the gentle lilac of his hair shifting to a warm, sympathetic pink. "Not at all. Truth is its own reward. But tell me, Madam Pince, a woman of your dedication, upholding the sacred trust of this institution… You must be utterly overworked, always on the go, never a moment to pause, never a moment to rest. I bet you have to stand and eat your meals, don't you? Maybe even have your food magically float beside you as you walk around, shelving books between bites."
Madam Pince let out a small, miserable puff of air. "That… has happened a time or two, yes."
"A time or two?" Echo repeated, his voice rising in soft, theatrical outrage. "A travesty! Having that happen once is a profound disrespect to your service! You deserve better, Madam Pince. You deserve comfort. You deserve a moment of genuine, quiet respite."
Echo gently took her arm—a gesture of such unexpected tenderness that Madam Pince momentarily forgot how to protest. He led her a few steps back, toward the small, rarely-used fireplace near the back wall, where a tiny, pathetic flame usually flickered. Before the hearth, he had silently summoned a beautiful, wingback velvet armchair in a rich, dark emerald green.
"Here," Echo murmured, his voice persuasive and soft. "Please, sit and rest for a moment on this nice, soft velvet chair instead of that rickety old wooden splinter-factor you usually sit at by the desk—the one that creaks when you so much as breathe. Just for a minute."
Madam Pince hesitated, her eyes flickering nervously to the distant end of Aisle 7, where the three Marauders were presumably still working. "But the boys… my post…"
"Nonsense," Echo insisted, applying gentle, irresistible pressure to her arm. "The boys will be fine. They're working. They won't dare move. They're terrified of you, which is precisely as it should be. Now, sit."
Madam Pince, as if controlled by an external force, slowly sank into the luxurious velvet. Echo produced a small, fluffy pillow from what seemed to be thin air and gently tucked it behind her lower back.
"There," he said with a satisfied nod. "A little support for your neck and back."
He then conjured a small, matching velvet ottoman and pulled it to her feet. "And put your feet up, Madam Pince. It's bad to be on your feet day and night, absolutely terrible for circulation."
Madam Pince's spine, which had been rigidly straight for decades, slowly relaxed into the velvet. She let out a long, unexpected sigh of relief. "Oh," she whispered, her eyes closing for a brief second. "That does feel a lot better."
Echo smiled, his pink hair warm and sincere. He conjured a steaming cup, handing it carefully to her. "Here. A little something to warm you up."
Madam Pince lifted the cup and inhaled the aroma. Her eyes snapped open, a flicker of recognition crossing her face. "Chamomile," she stated, her voice returning to a more familiar, if softer, tone.
"I heard it's your favorite," Echo replied, his eyes wide and earnest. "Unless I got that wrong?"
"No," she admitted, taking a long, warming sip. "I do like it."
Suddenly, a cold chill ran through the small alcove, making both of them shiver involuntarily.
"Oh, my," Echo said, rubbing his arms. "It must get so cold in here. That's awful."
Madam Pince shivered again. "The library is awfully drafty this time of year, Mr. Echo. Always has been."
Echo instantly threw a few more thick logs into the tiny fireplace with a silent flick of his wand, causing the flames to roar to life with immediate, magical heat. He then offered her a thick, heavy tartan blanket.
"Allow me," he said, gently draping the blanket over her legs. "We can't have the guardian of all this wonderful knowledge catching a chill. Now, have some more tea." He subtly refilled her cup from a hovering teapot he'd silently conjured.
Madam Pince paused, the cup halfway to her lips. She stared over the rim at Echo, her face unreadable. The warmth, comfort, and sincerity had finally broken through her shell of bewilderment, revealing the deep-seated suspicion beneath.
"Mr. Echo," she said, her voice dry and low. "What exactly are you planning?"
Echo looked at her, his pink hair softening to a sweet, innocent rose. He gave her a disarmingly sincere smile. "I'm planning nothing, Madam Pince. I'm simply thanking a wonderful witch for her service and ensuring her comfort."
He gave her a look of earnest, slightly wounded disappointment. "Honestly, Madam Pince, I assure you my motives are pure," Echo insisted, the rose in his hair solidifying into a deep, gentle magenta—the color of genuine, if slightly theatrical, feeling. "I merely want to ensure that the more overlooked members of the Hogwarts staff get even the smallest amount of respect they deserve. Between you and Mr. Filch, I'm not sure who gets the shorter stick."
He paused, letting his gaze sweep the library again. "Dealing with rowdy students, professors who don't take your advice about archival methods, and several people going into the Restricted Section thinking you're keeping that knowledge locked away and hidden like it's illegal when it's only mandated to be given out with proper permission. And let's not forget Peeves and all he does; I'm not sure which one of you has to deal with him more."
Madam Pince sighed, a sound of profound, weary agreement. "That is true, Mr. Echo," she admitted, her voice softer than he had ever heard it. "Especially about Peeves. The amount of dust he throws into the Non-Fiction section alone…" She trailed off, taking another long sip of the warm chamomile tea.
The warmth and the tea were clearly having a powerful effect. She let out a soft, feminine yawn, placing the back of her free hand delicately to her lips. Echo was instantly there, taking the cup from her hand. A soft, mournful string melody—the gentle opening notes of a forgotten lullaby—began to play from somewhere unseen within the library shadows. Madam Pince leaned her head back against the soft velvet of the chair, her eyes looking heavy.
"I never realized how tired I was," she murmured, her voice thick with exhaustion.
"You deserve a rest, Madam Pince, for all that you do," Echo said, his voice a low, soothing murmur, the magenta in his hair radiating silent peace.
Madam Pince yawned again, a long, deep, full-bodied sound. "Maybe I should rest my eyes for just a moment."
"You should absolutely do that," Echo said, his voice entirely devoid of artifice.
The moment her eyes fluttered closed, her breathing deepened instantly. The rigid spine of the Librarian of Hogwarts went completely slack. She was fast asleep.
Echo pulled the tartan blanket gently past her shoulders, covering her completely. He then bent down, leaned in close to her face, and snapped his fingers sharply right in front of her nose, a sound that cracked in the quiet library air. Her face remained utterly still, her sleep unbroken.
Echo smiled, the magenta in his hair instantly vanishing, replaced by a cool, clean, and utterly triumphant silver.
"Nighty night, Pince."
He straightened up, his movements quickening with purpose. He looked down the long, silent aisle toward Aisle 7, where three students waited. He walked away from the sleeping librarian, his steps silent on the stone floor. He walked away from the sleeping librarian, his steps silent on the stone floor. The three boys at Aisle 7 were still mechanically sorting and dusting. James, rubbing the scratch marks on his jaw, paused. He slowly straightened up, cocking his head.
"Is it just me, or did the air just get… lighter?" James murmured, looking around the towering, dusty shelves. The oppressive silence that had been hanging over them for an hour had lifted, replaced by a strange, almost serene quiet. "It's like the whole library just collectively let out a sigh of relief."
Sirius, who had stopped his sorting to lean against a stack of books, nodded slowly. "Yeah, I noticed that too. And wait… can you hear that?"
He tilted his head further, listening. A soft, gentle melody—the faint, mournful string of the lullaby that had put Madam Pince to sleep—was barely audible, drifting through the ancient aisles. "It sounds like… sad, quiet music. It's actually quite soothing. Wherever Pince is, she's not here."
Suddenly, three heavy, leather-bound volumes—the treatise on trans-continental portkey travel, which Echo had just tucked into his robes—floated out from the shadows above the boys' heads. They hovered for a brief moment, then descended swiftly and brutally.
Thwack! Thwack! Thwack!
The books slammed into the heads of James, Sirius, and Peter, one after the other, three sharp hits each. They yelped in unison, clutching their now-sore heads. A high-pitched, manic giggle echoed off the stone ceiling.
"PEEVES!" James roared, rubbing the newest lump on his head with an expression of furious pain.
The Poltergeist materialized instantly, hovering upside-down just above the shelves, his wide, wicked grin splitting his face. He tossed the three books into the air like juggling pins. "Ooh, a fresh bruise for the King of the Marauders!" Peeves cackled, his voice a grating shriek. "Peeves thought the three dumb-dumbs who always get into trouble could use a bit of extra knowledge! And since you lot can't absorb it through reading, why not deliver it directly through your thick, thick heads? Think of it as a scholarly concussion!"
"You're a menace, Peeves!" Peter squeaked, tears of pain welling in his eyes.
"A menace that's helpful," a calm, familiar voice corrected from the end of the aisle.
The Marauders spun around. Echo was leaning casually against the bookshelf, his arms crossed, his hair a subtle, victorious silver. He was watching the Poltergeist with a small, amused smile, his expression entirely relaxed. The gentle rose in his hair was a stark contrast to the angry magenta of James's.
"Echo?" James, Sirius, and Peter said in confused unison.
Echo pushed himself off the shelf, walking toward them with a light, purposeful step. "Evening, gits," he said, his silver hair glittering faintly in the gloom. "Finished your brain-boosting session with the Poltergeist? Good. You guys ready to ditch this intellectual torture chamber?"
Peter stared at him, his face a mixture of relief and disbelief. "Ditch? But… what about Pince? She'll skin us alive!"
Echo grinned, a sharp, challenging smirk that promised trouble. The silver in his hair flashed with pure mischief. "Madam Pince? What about her?"
Sirius narrowed his eyes, a glint of deep suspicion in his dark gaze. "What did you do, Echo? Did you hex her?"
Echo rolled his eyes with spectacular drama. "Relax, Sirius. I didn't hex her. She's just… resting."
Peter let out a high-pitched, strangled gasp that echoed faintly in the cavernous hall. "Resting? Oh my God, you killed her!"
"I DID NOT KILL HER!" Echo roared, the sound a furious, contained whisper that was still deafening. The silver in his hair instantly snapped to a furious, vibrant crimson. He leaned in close to Peter's face, his eyes blazing. "She is not resting in peace, you idiot, she is simply resting! As in, taking a very deep, magically-induced nap! She's sleeping, Peter! Sleeping!"
Peter sagged in instant, profound relief. "Oh. Sleeping. Thank Merlin."
James, adjusting his glasses, looked at Echo with a new degree of cautious respect. "Wait, you actually managed to get Pince to sleep? No one has ever done that. How, Echo? You can be a parseltongue, but you're not usually this smooth."
Echo's furious crimson hair instantly softened to a smooth, smug gold of pure pride. He tucked his hands into his robes and offered a casual shrug. "Well, James, I may be a parseltongue, but with a bit of planning, I can be quite the silver tongue. Also, a few kind words, a nice tartan blanket, and some chamomile tea with a light sleeping tonic for good measure."
Peeves, who had been listening with rapt attention, let out a loud, mocking cough.
Echo sighed in mild annoyance, turning to the floating Poltergeist. "And yes, fine. With a little bit of help from my favorite, most destructive friend. Thanks again for the chilly wind and the soft music, Peeves. Highly effective, as always."
Peeves grinned, his head bobbing excitedly. "Yes, yes, the deal! You remember the deal, little Slytherin?"
"I do, Peeves," Echo said, his gold hair gleaming. "The deal was, if I managed to put Madam Pince to sleep and vacate the premises for these three buffoons, you get to do whatever you want to the library—for one hour—without anyone stopping you. And since she's asleep, you are now free to do as you please."
Peeves let out a high-pitched, maniacal cackle, his eyes gleaming with malicious intent. He spun around, pulling a small, black marker out of his sleeve. "Oh, the possibilities! I shall make the books dance! I shall put the Restricted Section in the middle of the Great Hall! I shall make a gigantic mountain of parchment and—"
"Whoa, stop, stop," Echo interrupted, holding up a flat, dismissive hand. "Hold on, Peeves. You're being entirely too obvious."
The Poltergeist froze mid-cackle, his marker-wielding hand dropping. "Obvious? What do you mean, obvious?"
Echo stepped closer, his voice dropping to a conspiratorial whisper that drew the attention of all four. The gold in his hair faded to a sly, thoughtful blue. "Think bigger, Peeves. You don't want to change the books. That's messy and temporary. You want to change the library. Permanently."
Peeves tilted his head, intrigued. "Change the library? How?"
"The bookshelves, you little menace," Echo drawled, his voice thick with malicious suggestion. "Don't move the books. Move the sections. Put Aisle 8 into Aisle 2. Swap Aisle 3 into Aisle 27. Take the row full of old, highly detailed medical journals with all the pictures of, well, boobs and genitals, and move that row to the section where the first-years go for remedial reading. And, of course, move the entire Restricted Section to wherever you think is the absolute worst, most inconvenient place."
Echo paused, letting the full weight of the idea sink in. "Imagine the confusion. Everyone will be so utterly lost. Madam Pince will wake up tomorrow morning, thinking she has had a complete nervous breakdown and has moved the entire library around herself. She'll spend a week looking for a book she shelved yesterday, wondering if she finally went mad."
Peeves's eyes widened, a slow, terrifying smile spreading across his face. He let out a piercing, high-pitched giggle of unadulterated pleasure and clapped his hands together, the sound echoing throughout the silent hall.
"Peeves loves it!" he shrieked, vanishing with a loud, excited pop, the sound immediatelyfollowed by the dull, grinding scrape of ancient stone shelving as it began to move.
Sirius, his mouth slightly ajar, watched the spot where Peeves had been. "You know, sometimes I think I'm the biggest menace in this school, and then you open your mouth, Echo. That's pure evil."
Echo merely smiled, his silver hair now flashing with triumphant gold. "That's just how I roll, Sirius."
James, rubbing his newest bruise, looked at Echo, the relief on his face tempered with a hopeful, cautious curiosity. "So… this means we're forgiven then, Echo? You know, for the whole jam tart thing? Since you went to all this trouble to spring us?"
Echo's triumphant gold hair instantly snapped to a cold, flat silver. A humorless chuckle, sharp and dry as a winter twig snapping, escaped his lips. He slowly walked toward James, his eyes, which had softened to the smug blue of a moment ago, darkening to a cold, deep violet.
"James," Echo drawled, his voice sickeningly sweet, the tone devoid of any warmth. He came to a stop directly in front of the taller boy, then reached out, his grip closing like a vise around James's shoulder.
James immediately winced, his face tightening with a brief flash of genuine pain under the unexpected, brutal pressure. Echo leaned in, his voice dropping to a low, intense snarl that only the three Marauders could hear over the distant scrape of Peeves moving the library shelves.
"Forgiven? James, you insolent git, I haven't even considered the thought of it. You made a public spectacle, you got me an extended detention, and you turned my perfectly executed political move into a food fight. I was forced to perform the most desperate piece of magical theater of my life to cover your tracks just now. You got the short end of the stick? James, you haven't seen the stick I've prepared for you."
The deep violet in Echo's eyes burned with a fiery intensity that made James shrink back instinctively. Sirius and Peter exchanged nervous glances, both stepping slightly away from the epicenter of the conflict. Then, as suddenly as the coldness had descended, it vanished. The fiery violet receded, replaced by a tired, serious gray. Echo's fingers instantly released their death grip on James's shoulder.
"But," Echo continued, his voice returning to a neutral, pragmatic tone, as if the last forty seconds of barely contained rage hadn't happened. "Putting my entirely justified homicidal feelings aside, the three of you are needed by someone far more important than my bruised ego." He looked pointedly at Sirius. "Remus. Today is the full moon."
Sirius slapped his hand against his forehead with an audible thwack. "Oh, blast it, you're right! The Shrieking Shack!"
"And it's still Christmas night," Peter squeaked, reminding them.
James rubbed his sore shoulder, his face still pale. He winced again. "God, what a sucky day for a full moon."
Echo nodded, his gray hair softening to a quiet, sympathetic rose. "Yeah, it is. But he needs his friends, not his books, which is why I'm here. Now, get your animagus butts into gear and get going."
The three boys moved immediately toward the main doors. Just before they reached the threshold, Sirius paused and looked back at Echo, who was leaning back against a shelf, rubbing his temples with a weary hand.
"Aren't you joining us?" Sirius asked.
Echo let out a deep sigh. "I will. I told Remus I'd be right back, and if I don't show up, he'll freak out." Echo pushed himself off the shelf, his gait suddenly heavy with exhaustion. "I just need a minute. That night just started, and I'm already exhausted after my little reverse werewolf ruse."
James paused again, his confusion outweighing his fear. "Reverse werewolf, what now?"
"It's a long story, James," Echo said, waving a dismissive hand. "Remus can give you the first half—you know, when the sun comes out—and I'll give you the other half." Echo spotted the steaming cup of tea resting on the corner of Madam Pince's ottoman. "Right now, I desperately need some tea."
Echo walked over to the sleeping librarian, picked up the cup of chamomile, and took a long, fortifying swallow.
Peter stared at the cup in horrified recognition. "Wait a minute, Echo. Is that… is that the same spiked tea you gave to Pince?"
Echo paused, the cup halfway to his mouth for a second sip. His gray hair flickered with a single, sharp burst of panicked yellow. He looked at the cup, then at the soundly sleeping librarian, then back at the three horrified Marauders.
"Oops," Echo said simply, setting the cup down with unnatural care. He reached into his robes and drew out a small corked vial of shimmering violet liquid. He held it out. "Can one of you drop this in my mouth when I—"
Echo didn't get to finish the sentence. His eyes rolled up into his head, the neutral gray of his hair snapping to a deep, dark black as he collapsed, pitching forward and hitting the dusty stone floor with a muffled thud. James moved instinctively, driven by the adrenaline of the entire disastrous night, and finally found a useful outlet. He lunged forward, sliding the last few feet on the polished stone floor, his hands shooting out just as Echo's limp body was about to meet the stone.
WHUMPF.
James caught him, pulling the dead weight of the boy into a shaky, awkward hold, his already sore jaw cracking with the effort. Echo's head lolled back against James's shoulder, his hair a startling, inky black against the pristine dark robes.
"He's out cold!" James grunted, struggling to hold the unconscious boy. "Peter, the vial! Hurry up!"
Peter, who had been frozen in horror, snapped to attention. He snatched the small, corked vial of shimmering violet liquid from Echo's numb fingers before it could slip and roll away. Just as Peter yanked the cork free, a loud, incredibly deep, rattling SNORT erupted from Echo's chest, followed immediately by a prolonged, deafening, and perfectly rhythmic SNORING that seemed to vibrate the very shelves around them.
Sirius clapped a hand over his mouth to stifle a hysterical laugh. "Merlin's beard, he snores like a dragon! Get that stuff in him, Pete!"
Peter didn't hesitate. He jammed the mouth of the vial against Echo's slack lips and upended the liquid. The violet fluid instantly vanished down Echo's throat. The effect was instantaneous and violent. Echo's entire body spasmed in James's arms. He let out a series of involuntary, high-pitched, and completely bizarre sounds: a sharp, choked SQUAWK, followed by a wet, rattling GASP, which transitioned instantly into a furious HONK. The rhythmic snoring cut off mid-gasp, replaced by a deep, wracking cough that shook his entire frame.
"Urrgh!" Echo spluttered, pushing himself upright with a sudden, forceful movement that nearly knocked James backward. He coughed again, bending over and clutching his throat as his black hair abruptly flashed to a sickly, panicked yellow-green. He took a few deep, gasping breaths, then slammed his hand against his forehead.
"Sour," Echo croaked, his voice raw and thick, sounding like he'd swallowed sand.
Sirius, having recovered his composure, looked from the empty vial in Peter's hand to Echo's shuddering form. "What the heck is in this stuff, Echo? It sounds and smells like old socks and turpentine."
Echo slowly straightened, rubbing his eyes. The yellow-green in his hair was already settling back into a weary, neutral gray. He looked at them with a tired, profoundly annoyed expression.
"Do you three know what Muggle 'smelling salts' are?" he asked, pushing himself off James's supportive grip.
The three Marauders nodded hesitantly.
Echo held up the empty vial. "It's that in liquid form. It is literally just a highly concentrated, magically enhanced solution of ammonium carbonate. One vial would be enough to wake the dead, but don't quote me on that. I haven't tested it." He winced, rubbing his throat again. "Seriously, that aftertaste is appalling."
He grabbed the abandoned teacup and took a large, cautious sip, grimacing at the flavor. "Right. No more sleeping potion-laced tea for this Champion. Let's go. Remus is waiting."
"You three go on ahead," Echo commanded, his voice muffled as he rubbed his hand over his chin. "I need to find a sink and scrub the taste of old socks, turpentine, and sleeping potion out of my entire mouth. Seriously, it's like my taste buds have declared a hostile takeover. I'll be there in five minutes, at the most. I need to let Remus know I'm going to be late—the last thing I need is him thinking my plan worked in the opposite way and everyone actually thinks I'm a werewolf."
Sirius nodded, already turning to leave. "Got it. Don't be long, though. It's rough tonight."
James and Peter agreed, Peter, snatching the empty vial of 'smelling salts' from his hand and tucking it into his own robe pocket with a nervous shudder.
Echo watched them sprint away down the main aisle of the library, their footsteps thankfully muffled by the distance and the thick rugs. As they vanished through the heavy doors, their urgent departure accompanied by the distant, rhythmic scrape and thump of Peeves enthusiastically rearranging the ancient shelves, Echo let out a profound, tired sigh.
He turned and walked back toward the sleeping Madam Pince, picking up the small, empty vial of sleeping tonic he had used to spike the chamomile tea. He knelt by the fire, casting a silent, powerful charm at the velvet armchair. The tiny, insidious trace of sleeping draught instantly vanished, leaving the chair and blanket perfectly clean and magically neutral. Echo then looked at the sleeping librarian, his hair settling back into a calm, pragmatic gray. He took a single, small silver coin from his pocket—a rare, slightly tarnished Drachma he'd received from Sniffles, who stole it. He gently tucked the coin into the thick tartan blanket near Madam Pince's hand, a small, silent token of apology and genuine gratitude for her service; however, the magic that had enforced her rest had been.
"Merry Christmas, Madam Pince," he whispered, pushing himself back to his feet.
He tucked his wand away, pulled his robes more tightly around himself, and, after one final, disgusted rub of his tongue against the roof of his mouth, strode out of the library, making a beeline for the nearest water source. He had a werewolf to calm down and a night to get through.