Harry decided he was going to have to break some rules, despite Dumbledore's words. He couldn't just leave this whole mystery behind.

The next day, Harry, Ron, Hermione, and Neville split up through the labyrinth of hallways with one destination in mind. They didn't want Vulchanova being alerted that all four Ambassadors were rushing somewhere together, so, with the help of Hermione, they'd mapped out a different route for each person that would lead them all to the same place.

The Potions classroom where Neville had seen Dumbledore one night.

Harry's route started at the dining hall, went in one direction up the stairs, came down two flights, and looped back around to the Potions classroom. It was going smoothly, Harry walking briskly through empty corridor after empty corridor, until he ran into a group of Durmstrangs working on something in the middle of a hallway and had to backtrack, making him the last person to meet at their spot.

"What kept you?" Ron said, looking at his watch. They wanted to finish poking around before the lunch period was over.

"I had to take a detour, there were too many people," Harry said, slightly winded.

Although Harry wasn't really sure what exactly they were looking for, he assumed the unofficial lead of the group.

"Let's start over there," he said, trying his best to be quiet.

The door to the Potions room was closed, as expected. Harry was pretty sure that there wasn't anyone inside. At least, he hoped there wasn't anyone inside. Either way, the group didn't try to open it. That wasn't what they were here for.

"Take that wall," Harry said to Neville, pointing to the wall across the hallway. Ron and Hermione set to work on the walls on either side of the door.

It was dark in the Potions hallway. The torches were extinguished, as no one had any reason to be near a classroom during break time. Harry held up his wand.

"Lumos," he said, and the tip ignited with white light.

"Good idea," Ron said, and in moments they were carrying mini flashlights and scouring the walls for anything out of the ordinary.

The stones of the walls were cracking and smelled damp and musty. Harry, coming across a patch of shiny clear ooze, decided not to touch the wall unless absolutely positive it was safe.

He was sure that they must look very odd, four floating lights and bits of their bodies illuminated in a dark hallway. It was eerie, shadows jumping about unexpectedly and the darkness outside the pool of wand light dark and thick. Having his friends nearby made the whole experience easier, however.

Stone bricks made up the structure of the hallway. Uneven and rough, it was hard to cover every crevice and make sure nothing was overlooked.

Harry turned his attention to the door itself. Made out of some kind of metal, it bore scratches and burns from failed experiments and years of use. There were rusting bolts holding the entire things together; and although it gave the impression of slowly wasting away, Harry knew that the door was actually very secure and hard to open. Viktor's struggles when introducing them to Blacke had been more than enough proof.

The door would not need to open in order to provide them with the information they sought. Harry felt around with his fingertips, the wand's light guiding his movements.

"Any luck?" Neville's voice resounded through the hallway. "There's nothing here but mildew and water. Ick."

Harry could hear him walking over to Ron and Hermione, who shook their heads in the dim lighting as well.

"Nothing yet," Harry said. "I'm not sure what we're looking for, but it could be basically any sign that Blacke is up to something. And why was Dumbledore here?"

"So, anything out of the ordinary, writing, loose stones, that sort of thing?" Hermione asked.

"Yeah, I suppose," said Harry. "Let's get back to it."

The next few minutes passed in silence.

Harry was just about to give up. He stood, his wand's light rising with him, and that was when he saw it.

The hallway was grimy, damp, and unappealing. The stone bricks seemed corroded and dirty. Yet when Harry moved closer to examine a brick a little lower than eye level, he found it surprisingly clean.

The stone was part of the arch that was around the door, and although it was rough to the touch and textured like its neighbors, Harry noticed it was slightly lighter, dry as parchment, and looked freshly scrubbed. Harry was extremely familiar with cleaning, as Aunt Petunia often set him to do the house chores. He stepped closer, holding the wand close to the stone.

There was a faint scent of cleanser. But why use a physical cleansing solution when you could wave your wand and clean off the stone?

Magic can be traced. Harry didn't remember who had told him that, but he had no doubt that it was true.

As his wandlight swept across the rest of the wall and his fingers explored the surface of the out-of-place stone, he felt something.

Immediately, he crouched for a better look. The clean brick in the wall had a tiny inscription.

The symbol of the Deathly Hallows.

Harry let out a loud whoop of excitement that startled the rest. They ran over to see what was going on.

"Look," Harry said excitedly, pointing at the special brick. "It's got his mark, and it looks different!" He whispered, trying to tamp down his rapid pulse.

"Bloody hell," Ron breathed, leaning in for a closer look.

"This is proof that something is connected. I just can't figure out what!" Hermione stared and chewed on her lip.

"Harry!" Neville hissed. His eyes were wide and he looked at Harry expectantly.

"What, Neville? I don't have time for this. Hang on a sec." Harry said, his eyes fixed on what Hermione was doing.

She reached out and hit the stone, hard.

"Blimey," Ron said. "What are you doing that for?"

"I'm seeing if it will move," Hermione said, grunting as she tried to pull it out of its place. To everyone's immense surprise, it shook, then started to loosen from the wall.

"It's working!" Harry said, holding his wand above them all so Hermione could see.

"Harry!"

"Neville, just shut up a minute."

Hermione had one more inch to go and they'd see what was behind the stone.

"But Harry-"

"Neville-"

"I've almost got it!" Hermione said, cutting them both off. "Something's got to be behind here; maybe a compartment, or..or…"

"May I ask what you are doing?" Professor Blacke materialized out of the darkness.

The four spun to face him, Ron hurriedly shoving the stone back in place. Harry scooted in front of it, his back pressing against their discovery.

Harry extinguished his wand slowly with a whispered command, cold dread seeping into his limbs. Professor Blacke couldn't be very fast...maybe they could make a run for it…

"This is no place for students during their lunch time. Come with me." His eyes glinted. He turned and walked up the hallway into the well-lit upper floor staircase.

Harry and the others exchanged worried glances, then hurried after him. They were in deep, deep, trouble.