Professor McGonagall quietly closed the door of the small tower. The Book of Admittance and the Quill of Acceptance were now safely hidden inside her robe's inner pocket.
She and Snape walked silently through the corridor back toward the Headmaster's office. The castle's stone walls cast long shadows in the twilight.
"We can't count on the Death Eaters making mistakes. We have to act fast, " Snape's words were suddenly cut off by a flash of silver light streaking through the window at the end of the corridor.
He raised his head at once, wand sliding into his palm. A silver leopard was sprinting toward them.
"Alastor's Patronus," Professor McGonagall said in a low voice, her brow tightly furrowed.
The leopard was graceful and luminous, landing lightly in front of them.
It opened its mouth wide, and Alastor Moody's gravelly, deep, and urgent voice burst through the corridor:
"Scottish Highlands, Glencoe Valley! Death Eaters attacking! Requesting immediate aid from Dumbledore! We can't hold much longer!"
"What?" McGonagall exclaimed, her face turning pale in an instant.
She instinctively looked toward the Headmaster's office, where the real, weakened Dumbledore lay unconscious.
"I'm sorry, Alastor," she said to the Patronus, her voice trembling. "You'll have to handle this on your own. Albus is... unconscious..." She didn't finish the sentence.
The Patronus was silent for a brief moment. The silver light around it flickered faintly, and in its magically-formed eyes flashed a very human heaviness.
"I'll do my best," it said briefly, then turned and bounded away, leaving only a few drifting trails of silver light.
McGonagall turned to Snape, gripping her wand tightly. "We need to move faster," she said urgently, her voice full of an intensity she rarely displayed. "I'll transfer Albus to the ship's cabin later."
Snape nodded, then separated from her and made his way to the Room of Requirement, where Pandora and Lily were sorting potion ingredients.
"Hogwarts may soon be overrun by Death Eaters," Snape said directly, his expression grim but steady. "We're planning to evacuate the Muggle-born students."
"What happened? Why only the Muggle-borns?" Pandora asked, straightening up. "Isn't Hogwarts supposed to be the safest place?"
"Are you joking, Severus?" Lily asked sharply. "Professor Dumbledore, "
"That's Professor McGonagall impersonating him," Snape interrupted, watching both girls' faces fill with disbelief. "There's no time to explain. We need to act immediately."
Lily drew in a breath and nodded. "What do you want us to do?"
"Find all the Muggle-born students," Snape said. "Tell them there's a special school trip arranged just for them, could happen at any time, so they need to pack their things. Don't tell them too much; we don't want panic."
"Just the two of us doing this?" Pandora asked, already gathering scattered ingredients.
"Uh..." Snape thought for a moment. "Tell Barty and Abbott as well. They're better at this kind of thing."
He had chosen to trust young Barty now. After all, he had witnessed Barty's change with his own eyes, there was no longer any reason to doubt him.
"Myrtle," Snape said, glancing up at the ghost drifting near the chandelier. "You shouldn't stay here these days. Come with me."
"All right," Myrtle said cheerfully, fluttering down. "Are we moving again?"
In the following tense hours, the professors worked around the clock to finish the Founders' Ark. Most students were unaware of any of this, continuing their classes as usual.
Professor Slughorn, drenched in sweat, was fine-tuning the potion lab in the ship's cabin. Professor Sprout directed house-elves as they carefully transported Mandrakes and other potted magical plants aboard.
Professor Flitwick stood on scaffolding at the stern, wand tracing intricate sigils through the air as he reinforced the complex wards. His small face was tight with concentration, occasionally pausing to wipe sweat from his brow. "One more layer... must make sure it's flawless..."
Meanwhile, Professor McGonagall shuttled tirelessly between the castle and the dock, maintaining Dumbledore's illusion of health while overseeing the final preparations. Dark circles had formed beneath her eyes, yet her back remained perfectly straight.
On the third morning, just as the first rays of sunlight crept over Hogwarts' towers, Hagrid's enormous figure stumbled into the Great Hall. His beard was frosted white, and his rough coat was torn in several places.
"Professor!" he bellowed breathlessly as he ran toward the staff table, his booming voice silencing the entire hall. "There're strangers outside the school! I fought one of 'em!"
The Great Hall fell into stunned quiet. Every student's gaze turned to "Professor Dumbledore."
"Professor Dumbledore" rose solemnly, blue eyes sweeping calmly across the long tables.
"Everyone, continue eating," McGonagall said in Dumbledore's gentle tone, but Snape could hear the tension in her voice. "Horace, please keep watch over the students."
"Come with me, Rubeus," she said quickly to Hagrid, then shot a meaningful glance toward Snape.
Snape understood immediately, quietly signaling for his friends to follow.
The moment they stepped out of the Great Hall, McGonagall's tone changed to her usual stern command. "Tell me everything."
Startled by her voice, Hagrid hastily gestured with his large hands. "Saw three Death Eaters near the Forbidden Forest, masked, all of 'em. One of 'em spotted me, so we fought, bare fists, not wands."
He paused upon noticing Snape and the others approaching.
"Go on," said "Dumbledore," with a hint of McGonagall's impatience breaking through her disguise.
"All right," Hagrid lowered his voice. "At least six Death Eaters near the forest's edge. They seemed to be testing the wards. I drove one off, but the rest, they looked like they were waiting for orders."
"And they mentioned... Professor Dumbledore." He glanced uneasily at "Dumbledore" himself. "Said, 'Tell that old man to come out, or we're coming in!' and the like."
Snape and McGonagall exchanged an alarmed look, both realizing the gravity of the situation.
"They're suspicious," Snape said quietly.
"Severus," McGonagall decided instantly, "gather all the Muggle-born students immediately." She turned to Barty and the others. "Go help him. Hagrid, with me, we need to raise the defenses."
At once, Snape and his group returned to the Great Hall, quietly passing instructions to the older Muggle-born students.
The message spread like wildfire among a select few, while others looked on in confusion as their classmates suddenly left mid-meal.
Hogwarts descended into a quiet but chaotic evacuation. The Muggle-borns, bewildered, were ushered through secret passages toward the docks beneath the castle.
"A special trip? Now?" asked Edd Smith in confusion. "We still have Charms class."
"Professor Dumbledore approved it," Pandora said soothingly, her light hair disheveled from running. "It's a surprise activity, come on."
They scoured every corner of the castle, dormitories, the library, washrooms, greenhouses, even the Astronomy Tower.
Even Moaning Myrtle helped, her translucent body gliding through walls as she called for the students to hurry.
Meanwhile, McGonagall and the other teachers activated Hogwarts' ancient defensive enchantments. A translucent golden barrier rose slowly, enveloping the castle and its grounds.
That action only confirmed the Death Eaters' suspicions, if Dumbledore were truly unharmed, Hogwarts would never take up a full defensive stance.
Spells began to flash at the forest's edge as the Death Eaters tested the barrier's strength again and again.
"The more we defend," Barty muttered to Snape, "the more certain they'll be that something's happened to Dumbledore."
"As long as we can buy time," Snape said heavily.
By the time fifty-three Muggle-born students had gathered at the hidden dock, the sky was already at its zenith.
The Founders' Ark floated quietly on the turquoise waters.
Professor Flitwick, Hagrid, holding Fang's leash, and Filch, clutching Mrs. Norris, were directing the students aboard in an orderly fashion.
Meanwhile, the Death Eaters' attacks grew increasingly violent. Students trembled as they boarded, the sound of spells echoing across the lake.
"All accounted for," Snape said to Professor McGonagall as she arrived.
His eyes swept over the group: Pandora, Lily, Abbott, Barty, and Eileen, every familiar face was there.
Eileen gave him a small nod before following Professor Sprout to the ship's greenhouse to oversee the magical plants.
McGonagall, back in her own form, took the list from Snape's hand and frowned. "No, there's still one missing." Without another word, she turned and hurried off.
That's impossible, Snape thought. Everyone should be here. Who could be missing?
Then again, there were some people who didn't need to leave...
"This will be a difficult journey," he said quietly to his friends. "For those of you not Muggle-born, this isn't something you have to do."
Before he could continue, Pandora rolled her eyes and stepped forward. "Don't be ridiculous, Sev. You talk like you're Muggle-born."
Snape grasped her hand lightly, feeling the warmth of her fingers.
"What, planning to ditch me?" Abbott smacked his shoulder. "I haven't even had the chance to hang you upside down yet."
"Anytime." Snape replied.
"What are you staring at me for?" Barty asked, grinning. "If what you say is true, and the Death Eaters take power, then we'll all be fugitives from the Ministry, won't we?" His smile widened. "Imagine that, me, a wanted man. My dear father would just love that."
Even in this moment, Snape couldn't help the faint smile tugging at his lips. So Barty would walk his path after all.
Looking at each of their familiar faces, Snape nodded.
Before long, McGonagall returned.
And the four people behind her made Snape freeze, James, Sirius, Remus, and Peter Pettigrew.
"They're not Muggle-born, Professor," Snape said, blocking the boarding ramp. His friends immediately stood at his side.
"Peter is Muggle-born," McGonagall said wearily. "Let him through, Severus."
Snape stared in disbelief at Wormtail. He had assumed the boy, cowardly though he was, was at least half-blood. After all, in the original timeline, he had even become a Death Eater.
"I don't trust him," Snape said coldly, unmoving. "Even if he's Muggle-born, I don't want him on this ship."
A thunderous explosion echoed from afar, the barrier rippling under a blast of green light.
Time was running out.
"We can't leave him here, Severus," McGonagall said firmly. "Why don't you trust him?"
Snape was speechless. He couldn't very well explain that it was because of things that hadn't happened yet.
He fixed his eyes on Wormtail, who was shrinking back behind Sirius, craning his neck nervously with those shifty little eyes darting about.
Another blast against the barrier reminded Snape that this was no time to argue.
He stepped aside at last and said calmly, "I'll be watching you, Wormtail. You'd better behave."
"I won't, I swear!" Peter squeaked, nodding frantically as he scrambled aboard.
But Sirius and the others followed right behind him, preparing to board as well.
"Wait," Snape said again, blocking the way. "You three aren't Muggle-born either."
"We're staying with our friend," Sirius said, stopping James before he could speak. "Just like your friends are staying with you, bloodline doesn't matter." He glanced toward Pandora and the others. "Not to us."
"Friends?" Snape said softly, then stepped aside from the gangway. "Sirius, let's hope you don't make the same mistake again."
Sirius gave him a puzzled look, then followed the others aboard.
Once everyone was on, Professor Sprout emerged from the greenhouse and hurried ashore.
Professor Flitwick activated the ancient enchantment.
The Founders' Ark began to drift from the dock. Sprout stood waving from the shore as it departed.
The ship slipped out from beneath the ivy canopy and onto the black lake.
The Death Eaters had ceased their assault, staring silently after it.
A deep, resonant horn echoed across the water.
Then, at the lake's center, the surface began to churn violently, waves crashing against the damp shore. In the middle of the lake, a vast whirlpool appeared, as if some enormous stopper had been yanked from the bottom.
Amidst the Death Eaters' shouts of alarm, the Founders' Ark lurched downward and vanished beneath the stormy waters.
The waves closed over the stern. Standing on deck behind the magical barrier, Snape gazed at the place that had been his home for seven years disappearing into the depths.
His friends quietly gathered beside him, all of them staring in silence toward the same direction.
Merpeople swam nearby, singing ancient songs of farewell.
"Hogwarts was never just this castle," McGonagall said loudly, repeating the same words from before, but this time, it sounded as though she was trying to convince herself as much as the others.
"We'll be back," Snape said to her, looking into the deepening darkness.
The ship carried them onward, sailing into the unknown waters ahead.