"Hey, you lookin' for a duel?!" Tonks challenged as she brandished her wand only to notice that Harry wasn't looking at her but behind her. Turning her head, along with Penny, the three stared at the door that was next to the chalkboard. After all, that door hadn't been there a minute ago.
"That's new." Harry remarked as he slowly approached the newly revealed door.
"Careful, we don't know why this door appeared or where it might lead." Penny cautioned her wand already in her hand. Tonks followed along, her wand pointed forward and ready. Upon reaching the door Harry noticed something on the ground in front of it. Crouching down to look close at the object Harry noticed the runes covering it. It was made of wood and was around fifteen centimeters long and eight centimeters wide. Tapping the wooden object with his shoe to see if it would react yielded nothing, so Harry slowly picked it up.
"The heck is it?" Tonks asked as Harry stood up with the object in hand.
"Give me a moment." Harry requested already distracted by looking over the runic sequence on the wood. A little over a minute later Harry grinned as he'd finally figured out what he was looking at. "This is a Sight Lock."
"A what?" Penny asked confused. Tonks looked equally confused by the term.
"A type of Ward Object. It's similar to the Hiding Stone but it makes whatever object it's placed on completely invisible. Even if someone is directly looking for said object they won't be able to perceive it or the Sight Lock even if they're both right in front of them. Its only weakness is that it can be removed by anybody. It also has the limitation of only working on objects and doesn't function on people. I saw a basic design for one in my Advanced Magical Crafting book." Harry explained as he set the Sight Lock on a piece of parchment on top of his work table and the parchment and the Sight Lock disappeared from Penny and Tonks' sight.
"So only the one that places it can see it?" Penny questioned getting a nod from Harry as he picked it up and the parchment reappeared. Tonks had a mischievous look on her face as she looked at the Sight Lock. Oh the pranks she could play with that little item!
"The only thing strange is why it's still working. Sight Locks are supposed to be charged with the placer's Magic and that disperses after a day or so at best. This one was still working possibly since the last time this classroom was used." Harry puzzled over the strange Sight Lock. "I'll have to go over the runic sequence in full to determine why it was able to keep working. But first let's see what's behind the door." Penny and Tonks both raised their wands again as Harry carefully examined the door for any more surprises. Not finding anything Harry tried to open the door. The door didn't budge and Harry guessed it was locked. A wandless Alohomora made the lock click and Harry gently pulled the door open. Inside was a fairly large room which Harry estimated to be roughly thirty or so square meters. It had a couple of windows on one wall that overlooked the back courtyard of the castle. As the trio slowly moved into the room Tonks moved over to a smaller door and opened it to discover a full bathroom with a shower, bathtub, sink, and toilet.
"I think I know what this room is." Penny stated getting Harry and Tonks to look at the Prefect. "This is probably the Professor's quarters. According to 'Hogwarts: A History' back when the school had far more students, many of them permanent live-in, there were far more Professors. I think each subject use to have a minimum of three Professors, but each Professor's classroom also had their quarters attached. This was probably the Ancient Rune Professor's quarters before they left."
"But how long ago was that?" Tonks asked as she looked around the room, if it had been locked up and hidden like this then the small amount of dust made sense. Especially if it was even hidden from the House Elves of the castle, those little ones would be appalled at even this small amount of dust. Then again some of the other abandoned classrooms she'd found in her years here had been left in a state of neglect. Maybe the House Elves eventually left rooms that weren't used alone?
"The last time that there was more than a single Professor for any subject was in the late Eighteen Hundreds. If I remember correctly, that is." Penny replied as she looked out the windows at the rarely used rear courtyard.
"I could use this space." Harry nodded to himself. Penny immediately noticed the look on Harry's face and sighed as she prepared to burst his bubble.
"Harry, you can't move into this room. It's against the rules and I'm supposed to help enforce them. You also know that people would quickly realize you weren't staying in Ravenclaw Tower anymore. You might be able to get away with staying here overnight a couple of times a school year but any more than that and someone is definitely going to notice." Penny explained getting Harry to sigh and nod in acceptance. He looked over the largish room again before really focusing on the windows. Suddenly a grin came to his face as a problem he'd been having might finally be solved.
"What's that look for, Harrikins?" Tonks asked upon seeing Harry's expression. Harry turned to smile at both his friends before explaining his change in mood.
"You know how I was lamenting the slow increase in my Transfiguration skill and how it was limiting my ability to craft with metal?" Harry asked and received nods in return. "Well, I've been racking my brain trying to figure out a way to either rapidly increase my Transfiguration skill, which isn't likely, or find a place to build a forge and shape it the old fashioned way. This room has everything a proper blacksmith workshop needs with only a few minor modifications." He explained happily as he surveyed the room to plan where to put things for his blacksmithing. He may only know the most basic of the craft but that wasn't anything some experience and studying couldn't fix!
"Harry, I'm not sure that's allowed." Penny started only to have to stop and actually think about it. Were there any rules against setting up a blacksmith workshop in Hogwarts? The school had a history spanning a thousand years, so surely this kind of question had come up beforehand, right? "At least let me check the rules before you start building or setting up? I don't want you getting in trouble." She asked getting a nod from Harry even as he continued to roughly measure stuff in his mind.