Just as the two were leisurely having a tea party in the Ravenclaw common room, almost every passageway in Hogwarts had been turned upside down.
Hermione's pet, the fat Crookshanks, was leading the charge in front of a squad of Iron Guards. Its ginger-yellow, chubby body displayed an agility completely incongruous with its size. Its fur stood on end, radiating aggression, while its flat face was filled with anger, its apricot-yellow eyes narrowed into slits.
At first glance, it seemed as though the guards were driving it away and that it was fleeing in a dishevelled state.
But that was merely an illusion.
In fact, it was leading the way.
Crookshanks was remarkably perceptive, and it had sensed that Hermione was in danger.
Ron and Harry followed behind, panting, along with Moaning Myrtle, who had been rescued and was now floating beside Professor McGonagall's shoulder, waving her arms urgently as if apologising.
The commotion was quite loud, and the classroom had been left in complete disarray by Myrtle.
"Potter, Weasley, you can go and find Miss Granger now. She may be in some danger. There are definitely outsiders infiltrating Hogwarts. As for Crookshanks, he should know where she is. Flitwick and I need to continue searching for the intruders."
The old woman spoke swiftly and decisively. She then adjusted her black pointed hat and, together with the short Professor Flitwick, turned and headed down another corridor that had not yet been searched.
After Professor McGonagall assigned them their tasks, the group parted ways.
The two boys and the cat hurried upstairs toward Dumbledore's office, followed by a group of guards in black armour.
As for Professor McGonagall, she soon reached the end of the corridor, where she and Professor Flitwick stopped in front of the Ravenclaw common room.
They began searching the area.
A knocking sound rang out, followed by the rhythmic thud of footsteps echoing down the corridor.
They were both rapid and perfectly measured.
"To access the Ravenclaw common room, you need to answer some questions."
The gentle voice sounded again.
"Filius!"
Malfoy and Luna heard Professor McGonagall call for Flitwick again.
The Head of Ravenclaw House probably would not be stumped by a test at the entrance to his own common room.
Flitwick stepped forward. Normally, this should have been a piece of cake for him.
But today, perhaps an exception would have to be made.
The door opened its mouth and began asking a question in its soft voice.
"Imagine a ship that has sailed the seas for hundreds of years. Its captain is a Muggle, not a wizard, and there are no Levitation Charms or other spells cast upon its hull. Its longevity is entirely due to the crew's continuous maintenance and replacement of its parts. Whenever a plank rots, it is replaced, and so on, until none of its functional components are the originals.
"The question is, is the resulting ship still the original ship after all its parts have been replaced? If not, at what point did the nature of the ship change? Was it when the first part was replaced, the last part, or sometime in between?"
The gatekeeper spoke very quickly, posing the lengthy question in one breath.
The dull thumping of the steel guards outside stopped, and the wind blades slicing through the air ceased as well.
Flitwick's face showed an expression of extreme surprise.
Instead, an indescribable silence descended.
The air seemed to freeze with awkwardness.
Professor McGonagall's eagle-like eyebrows twitched.
The question left both Gryffindor's Head of House and Ravenclaw's Head of House deep in thought.
But after a while, they still had not come up with an answer.
"I don't know whether that ship would still be the same ship. I only know that if you don't open this door, one of the doors will be torn down."
Professor McGonagall's temper had become unusually volatile. Normally, she would have simply left, but things were different now. Combined with the blow of Dumbledore's death, she no longer had much patience.
"New Question Entry—Faced with an absolute threat of force, what decision should we make?"
Ravenclaw then answered honestly by demonstrating its abilities—it opened the door immediately.
They had absolutely no courage to face death.
But perhaps expecting courage from a door was asking a little too much.
As the two professors stepped inside, they heard a light and ethereal greeting.
"Hello? Professor McGonagall? And Professor Flitwick? Hello! Would you like to try some cookies? My dad made them."
Luna, sitting in a chair, waved and greeted them.
She sat alone in a soft blue armchair, swinging her legs back and forth as she fed herself the snacks her father had prepared for her. She looked completely content.
If there had been a few more people present, they might have thought a tea party was being held in the Ravenclaw common room.
Seeing the two professors enter, Luna stood up and politely greeted them again.
"Miss Lovegood? Has anyone been in here before us?"
Professor McGonagall stood beside the table, her brow furrowed as she declined the invitation to taste the cookies.
"I'm not sure. I didn't notice."
Luna shook her head, her eyes slightly glazed over.
"Don't you think it's a kind of sacrilege to focus on other things while someone is enjoying delicious food?"
Luna's remark left the two professors speechless.
"By the way, Professor McGonagall, if you really removed the Ravenclaw door and put it in the Gryffindor common room, would it still be the same door?"
Luna unexpectedly asked another question.
Professor McGonagall's face turned even paler.
"Let's go."
She turned to Flitwick.
The two left, and as soon as their backs were turned to Luna, she quickly waved to one of the armoured steel guards standing outside the door.
"Have a safe trip."
She mouthed the words before mischievously sticking out her tongue.
"Even with power, without precious wisdom, one can be easily deceived."
She whispered this under her breath.
McGonagall and Flitwick left the Ravenclaw common room.
They continued advancing in perfect unison with the group of armoured soldiers from the castle.
Wherever they went, the two professors cast spells to detect nearby magical fluctuations, since the intruders might have used a Disillusionment Charm to evade their search.
In that case, they would have to use counter-spells to dispel it.
Of course, they never imagined that while they were focusing their attention on Luna, someone had already quietly infiltrated the torrent of steel that made up their legion.
The intruder carefully avoided their detection range.
"Creak, creak."
McGonagall led the group of soldiers down the next corridor.
"Tap, tap."
However, what she did not notice was that at the very end of the black-iron army under her control, one soldier had fallen behind.
Even after falling behind, the soldier maintained the same rhythm as the others, merely changing from marching to standing still.
Eventually, it became completely separated from the group and disappeared without a trace.