It only took half a day for the group to complete all the necessary preparations.
Two explosive books were placed on the fifth and sixth floors, right above the corridor corners, at just the right distance to lure Filch over at any time.
Everything was ready.
But shortly after the group decided to embark on a nighttime adventure to explore the fourth floor, something unexpected happened.
Several upper-year Gryffindor students didn't even wait for curfew. They sneaked to the fourth floor while the others were having dinner.
However, unlike the Weasley Brothers, they didn't have any previous plans, nor did they have strategic tools like the Marauder's Map. It was just a spur-of-the-moment decision.
The result was predictable; they couldn't even open the door and were caught red-handed by the ever-vigilant Filch nearby, who took them to Professor McGonagall's office.
Before long, Gryffindor had lost fifty points from their hourglass.
But that was not the end.
In the following period, students from Ravenclaw, Slytherin, and Hufflepuff were sneaking out of their common rooms heading to the fourth floor.
Fred and George, who were watching the Marauder's Map, were stunned as names popped up frequently on the normally quiet corridors.
Perhaps too many young wizards had been caught, leading a few professors to confer and directly leave their offices, taking turns waiting for the night-exploring students near the fourth floor.
No matter who it was, anyone caught would face ten points deducted and detention.
It had to be said, professors were much more troublesome compared to Filch...
George lit some magical fireworks on the first floor, which burst into blooms upon contact with water, hoping to divert them.
As expected, Filch cursed under his breath and headed downstairs after hearing the commotion, while Professor McGonagall followed solemnly behind him.
Near the second-floor staircase, Fred, hidden in the shadows, sighed as he looked at the Marauder's Map, "Professor McGonagall is too much."
On the map, Professor McGonagall's name was still near the fourth floor, while Filch descended alone.
Clearly, the Professor McGonagall they saw earlier was fake, likely a high-level Transfiguration Technique.
Given the current situation, it's unlikely they'll be able to go exploring again. They discussed and decided to wait for the commotion to pass before returning to their dormitories.
...
This wait lasted three days.
Three days later, in the dead of night, four people quietly appeared in the school's corridors.
"Fred, George..."
Cedric, walking at the back, whispered, "Are you sure the professors are no longer going to the fourth floor?"
"We watched for a long time last night."
Fred whispered, "Since the weekend, the professors haven't gone to the fourth floor anymore, and tonight should be no exception."
"Almost there."
They stopped near the third floor, and George lowered his head to look at the Marauder's Map.
"We're in luck; the professors aren't here, nor is Filch... Oh, Merlin, guess who I see!"
"Who is it?" Fred asked with a smile, "It can't be Percy, can it?"
"It's not Percy; it's Ron..." George said in surprise, "And Harry, Hermione, and Neville; the four freshmen are in the trophy room at this time."
"Ah-ha..." Fred chuckled, "Already night exploring with friends at the start of school. Tsk, truly our little brother..."
"Clang clang..."
Suddenly, a series of crisp collision sounds rang out.
It seemed someone had knocked over the armor in the corridors; the sound of metal parts hitting the ground was very loud, especially in such a quiet environment, it was exceptionally piercing.
"Oh god, they've been discovered!"
George raised his head and said, "Now there are two pieces of news.
The good news is Filch's attention is now on Ron and his group, which is the perfect opportunity for us to act.
The bad news is they've made too much noise, and it's likely to attract the professors."
"Looks like we need to hurry."
Fred glanced at the map and sped towards the fourth floor.
On the map, Harry and Ron were moving quickly in their direction; at this rate, Filch would soon be drawn to them.
Upon reaching the fourth floor, they quickly followed the Marauder's Map instructions and arrived at a door at the end of the corridor.
"Students not sleeping!"
At this moment, Peeves suddenly yelled angrily from not far away, "Students not sleeping, in the Charm Class corridor!"
"I take back what I said before; Ron really is a fool after all."
George put down the Marauder's Map and extended his hand backward.
Soon, an ancient bronze key appeared out of thin air in his hand.
"Thanks, Kai..."
George inserted the key into the keyhole and gently twisted it to open the door.
"They're almost here; quick, go in... Oh, damn, what is this thing!"
As George was about to enter the door, he raised his head and saw three pairs of shining green eyes staring at him intensely.
Behind the door was a hallway with a monstrous large dog; what he had seen were its eyes.
It had three heads and was so large it filled all the space from the ceiling to the floor.
Once the door was opened, this three-headed dog stood up, its three noses twitching and trembling towards them.
Three drooling mouths suddenly opened wide, revealing rows of fierce yellowed canine teeth.
"Damn it, Dumbledore wasn't lying this time... Run!"
George couldn't afford to think any longer and instinctively turned around and sprinted.
Fred and Cedric also saw the three-headed dog and, as it lunged forward, any thoughts of adventure or curiosity... all vanished into thin air.
They were more than clear what the deafening roar meant.
No words were needed, nor did they require communication; the two quickly followed George and began running wildly down the corridor.
Even though doing so might get them discovered, faced with a choice between Filch and becoming dog food, they preferred Filch.
The three didn't look back and only stopped when they reached the kitchen door.
"Headmaster Dumbledore is really playing for keeps!"
George said breathlessly, "Merlin, he actually placed an adult three-headed dog in the school; what's he thinking?!"
"I'm sure there's something hidden underneath." Fred's eyes flashed as he said, "Did you notice? That dog was standing on a trapdoor."
George sighed and said, "It's useless; you can't expect it to make way for us."
"Wait a minute..."
At this moment, Cedric suddenly said, "Did any of you see Kai?"
"Didn't he come back with us?" Fred was startled and then realized there were only three people here.
Kai had vanished without a trace.