BOOM!
The sound was cataclysmic. It wasn't just a noise; it was a physical vibration that seemed to rattle the very foundations of Hogwarts. It was the unmistakable, bone-jarring roar of massive weight meeting solid stone—the kind of sound that didn't just wake people up, it sent them bolting upright in bed with their hearts hammering against their ribs.
On the third floor, Fred Weasley, who had been enjoying a rather sophisticated game of 'bait and switch' with Filch, froze mid-stride. He pricked his ears, his eyes wide under the invisibility of the Disillusionment Charm.
Filch, who had been lunging toward a faint sound of running footsteps, skidded to a halt. His greasy hair was disheveled, and his lamp swung wildly. He looked up, his face contorting into a mix of confusion and predatory glee.
"The fifth floor," Filch rasped to the empty air, his voice cracking with excitement. "Something big just broke. Something expensive." He didn't waste another second on the third-floor shadows, spinning on his heel and sprinting toward the grand staircase with an agility that belied his age.
"What in Merlin's name was that?" George's voice whispered from the air beside Fred. He sounded genuinely rattled. "That wasn't a fertilizer bomb. That sounded like the castle was being demolished."
"I have a feeling our resident genius overplayed his hand," Fred replied grimly. "We need to move. Now. Before the entire staff descends on this corridor like a swarm of angry Billywigs. Back to the common room, full tilt."
"What about the meeting point? What about Albert?" Lee Jordan's voice hitched, the adrenaline of the prank suddenly turning into the cold sweat of a potential expulsion.
"Albert Anderson is probably three floors ahead of us by now," Fred said, already breaking into a run. "The man has a survival instinct like a cornered kneazle. We don't go to the eighth floor meeting point—we go straight for the tower. If the professors are out, they'll be looking for anyone out of bed. We need to be behind that portrait hole five minutes ago."
Their logic was sound. Within seconds of the crash, the castle had transformed. Portraits were no longer snoring; they were leaning out of their frames, whispering urgently to their neighbors, some even scurrying into other paintings to spread the word. Several professors had been jolted from their sleep and were already throwing on robes, their wands lit.
Albert, however, was faster. He had vanished from the library seconds after his Reparo Maxima had finished its work. He hadn't just run; he had moved with a calculated, silent speed, pausing only to ensure the library doors were pulled shut and the latches clicked back into place.
It was this tiny, disciplined detail that would buy them their lives. When Filch finally burst onto the fifth floor, he found the corridor silent. The library doors were closed. To a casual observer, everything looked undisturbed. Filch knew the sound had come from here, but without a visible point of entry, he was left spinning his lamp in circles, frustrated and foaming at the mouth.
Albert, meanwhile, was a ghost in the halls. He avoided the main staircases, knowing the portraits were now fully alert and watching for the slightest shimmer in the air. He ducked behind a heavy tapestry on the sixth floor, slipping into a narrow, vertical flue of a staircase that only he and the twins seemed to know about. It was a straight shot to the eighth floor.
As he reached the landing near the Fat Lady's portrait, he didn't drop his charm. He stood perfectly still, his back against the cold stone, regulating his breathing. A few minutes later, the air rippled, and three frantic, invisible bodies nearly bowled him over.
"Why are we standing here?" Lee Jordan's disembodied voice hissed. "Open the door! Let's get in!"
"Hold your breath, Lee," Albert's voice whispered, calm and steady. "Look at the Fat Lady. She's wide awake. If we ask her for the password now, she'll see a floating void talking to her. Tomorrow morning, she'll tell McGonagall that four invisible students entered the tower at midnight. We can't go in. Not yet."
The twins went silent, the gravity of the situation sinking in. They had the Map, they had the charms, but they had forgotten the most basic witness: the door itself.
"Follow me," Albert commanded. "The Room of Requirement. We hide there until the heat dies down. It's the only place in this castle that doesn't exist unless we want it to."
They followed him down the corridor, their footsteps muffled by the thick rugs of the eighth floor.
While they were vanishing into the Room of Requirement, the library had become a hub of late-night tension. Severus Snape was the first to arrive after Filch, looking particularly ghoulish in a long, charcoal-grey night-shirt that billowed like a shroud.
"Filch," Snape drawled, his voice a low, dangerous silk. "Explain why you are shrieking in the hallway like a banshee."
"The noise, Professor! It was like the very shelves were being torn from the stone!" Filch pointed a shaking finger at the library doors. "I was chasing them—students! A pack of them, wandering the halls. I suspect Gryffindors, sir. It's always the Gryffindors."
Snape pushed past him, his wand tip glowing with a cold, white light. He entered the library, his eyes scanning the Restricted Section. He walked past the very shelves Albert had collapsed. He touched the wood, his eyes narrowed, searching for the tell-tale shimmer of a recent spell. But Albert's Reparo had been too thorough, and his natural talent for concealing his magical signature had left the air clean.
"There is nothing here, Filch," Snape said, his voice dropping an octave. "No fallen shelves. No misplaced books. Are you hallucinating in your old age?"
"I heard it! I swear on my life!" Filch protested just as Professor McGonagall arrived, her hair encased in a sturdy net, her tartan dressing gown cinched tight.
"What is the meaning of this disturbance?" she demanded, her gaze sharp enough to cut glass.
Filch repeated his story, adding more frantic details with every sentence. "A group of them, Minerva! I saw the shadows! They were in the Forbidden Section, I'd bet my last Galleon on it!"
"And yet," Snape interjected maliciously, "the library is pristine. Perhaps the 'shadows' you saw were merely the reflections of your own incompetence."
Before the argument could escalate, Professor Rowena Smith appeared, looking remarkably composed in a bronze silk nightgown. "Is this a pajama party? Or did someone finally decide to blow up the trophy room?"
"Filch claims Gryffindor students are currently roaming the halls," McGonagall said, her brow furrowed.
"Most likely," Snape added with a thin, cruel smile. "If you want the truth, Minerva, we need only check the source. Let us visit the Fat Lady. She doesn't lie for students—at least, not well."
The four staff members made their way to the eighth floor. The Fat Lady looked up as the group approached, her eyes wide with the excitement of the night's drama.
"Madam," McGonagall said formally. "Has anyone entered the common room in the last ten minutes?"
"No one," the Fat Lady replied promptly.
"And has anyone left?" Snape asked, his black eyes fixed on her.
"Oh, yes," she chirped.
"Who?" Filch demanded, stepping forward.
"I haven't the slightest idea," the Fat Lady said with a shrug. "They were invisible. Just a bunch of voices and a floating password."
Snape's face twisted into a mask of triumph. "Invisible. A Disillusionment Charm. This isn't just a simple prank; this is advanced magic. I suggest we perform a dormitory sweep immediately. We see who is missing from their bed, and we find our culprits."
"Absolutely not," McGonagall snapped. "I will not have my students terrified in the middle of the night because Filch heard a noise that apparently didn't happen. Waking the entire house is a step too far."
"The Disillusionment Charm is N.E.W.T. level magic," Smith reminded them, his voice smooth and reasonable. "If they didn't go back into the common room, they must still be out there. We don't need to wake the sleepers; we just need to catch the ones who are still hiding in the dark. I agree with Minerva—searching the castle is more efficient than a bed-check."
Smith's intervention settled it. Snape looked disappointed, but he couldn't argue with the logic. The search began in earnest. Professors and Filch spent the next hour scouring the secret passages, the trophy room, and even the owlery.
They did find someone.
A Ravenclaw girl and a Hufflepuff boy were caught huddled in a disused classroom on the third floor, looking guilty and thoroughly terrified. Filch pounced on them like a hawk on a field mouse.
"Caught you!" he shrieked.
They weren't the ones who had caused the crash—they were just two teenagers looking for a quiet place to talk—but the professors didn't care. Fifty points were stripped from each house on the spot. Under questioning, it became painfully clear they had no idea what was happening in the library. They were just the night's convenient scapegoats.
By 2:00 AM, the search was called off. The professors were tired, Filch was fuming, and the castle was declared 'clear.'
None of them, not even Snape with his suspicious mind, thought to check the blank stretch of wall opposite the tapestry of Barnabas the Barmy. Inside a room filled with comfortable armchairs, a roaring fire that produced no smoke, and a table laden with hot cocoa and biscuits, four Gryffindors were laughing quietly.
"You actually knocked over the whole shelf?" Fred asked, shaking his head in disbelief as Albert explained what had happened.
"The Summoning Charm was... more enthusiastic than I anticipated," Albert admitted, sipping his cocoa.
"And you fixed it all before Filch got there?" George asked.
"Every splinter," Albert confirmed.
They sat in the Room of Requirement, safe and sound, while the rest of the school suffered the fallout of their night walk. Albert looked at his friends, a small, satisfied smile on his face. He hadn't gotten the book he wanted, but he had learned something much more valuable: in Hogwarts, the best way to hide isn't to be invisible—it's to be where everyone thinks you aren't.