It was an unusually warm day on 25 Sept 1991, the sun was shining and many students were wishing they could be outside enjoying the unusual bout of warmth rather than sitting in their classrooms. It was for this reason that none noticed the disappearance of Fred and George Weasley during their third period History of Magic Class. The boys in question were not out enjoying the unusual weather and were instead on the ninth floor in a disused classroom.

They were sitting on the dusty floor and staring at an old piece of parchment in bafflement. The parchment itself had a long history, dating back to 1976 when it was created by the Illustrious Marauders; Messrs Moony, Wormtail, Padfoot, and Prongs, Purveyors of Aids to Magical Mischief-Makers. The Weasley twins had seen fit to steal it, and many other valuable pranking aids, from Filch's office in their first year. It was invaluable in planning pranks and general mischief as it showed every secret passageway within Hogwarts and where every person within Hogwarts was located at that particular moment.

Rather than planning mischief at that moment though, the twins were staring with deep concern at their younger brother Ronald and his new friend Harry Potter, along with an addition that they had been able to find no information about, Peter Pettigrew. Every time the twins had looked at the map since getting to Hogwarts this year the mysterious Peter Pettigrew was with their brother. They had done subtle digging, going so far as searching that year's, and even the past seven years' Hogwarts entry records to try to find out if in fact there was a Peter Pettigrew.

While it may seem absurd to others to so studiously check out a new friend of their brother's they had good reason to, for the very first time they had checked the map upon arriving at Hogwarts it had been the very first night back at Hogwarts, and Peter Pettigrew had been in bed with their brother! Concerned the boys had gone and checked and found no one extra in the room, or in bed with their loudly snoring brother. Every night since Peter Pettigrew had been in bed with their brother and they had not been able to catch him or in any way detect him.

They had a few very bad ideas about where he might be though, each scarier than the last. George brought up the fact that the map was known to show ghosts, at that particular moment Nearly Headless Nick was wandering around the Great Hall with the Fat Friar. It was not outside the realm of possibility that some entity; ghost, poltergeist, or other, was haunting their brother, though they knew no particular way that one would have attached to him. The range of ways they could harm his brother was startling and not even fully understood by the twins.

Or perhaps, George countered his own argument, he could be following around Ron using some form of invisibility; a cloak or spell, or some other unknown way. Though again the question was why? Why would anyone be so fascinated with Ron? If it weren't for the fact that he slept in the same bed as Ron it would almost be easy to assume that this Peter was following around Ron's new friend Harry, who was after all The-Boy-Who-Lived. But if that were the case why not sleep with or near Harry?

Fred, who had thus far been quiet about his own thoughts finally spoke up in the quietest voice George had ever heard him use when it was just the two of them in complete privacy. "Think about what Ron carries with him all the time since August." George furrowed his brow and then stared down at the map in shock. Scabbers. In August Percy had been delighted to learn that he had been made a Prefect and their mum had rewarded him by buying him a new owl which he had pompously named Hermes. When he'd learned he'd be getting an owl he practically tossed Scabbers the, now that the twins thought about it, abnormally old rat, at Ron.

"How long did Percy have him for?" George thought about his twin's question but he wasn't quite sure, Scabbers had simply always been there for as long as he could remember. Fred clearly couldn't remember either. The two thirteen year old boys stared at each other, for once feeling completely overwhelmed. There were too many possibilities, all bad, and not enough answers. "What do we do?"

Eventually it was decided that they would try to figure out a way to reveal animaguses and hidden spirits or people as that was the only avenue that they could think of at that particular moment. Thus it was that they had ended up spending an absurd amount of time in the library, pouring over books far above their age group. It had been quite a sight to their fellow classmates and Professors, the twins haunched over a table that was overflowing with books. They'd found great humor in the shocked look on Professor Flitwick's face, the suspicious look on Professor Snape's face and the nervous look on Professor McGonagall's face.

This unfortunately was the only thing they found humor in, as the books were several years above their age group and nothing remotely similar had been taught in their classes. Add to this the fact that they had no real way to practice and they were quite thoroughly stuck. That was until they were confronted a week later when they had decided to continue studying well into the night in the common room. Once more they were surrounded by books and were muttering to each other quietly and nervously, looking almost fearful to those who knew them.

Percy, who knew them quite well, had managed to restrain himself thus far from asking about their project. They weren't acting like they normally did when they were scheming so he'd had no reason to, but he'd never seen them acting so afraid and working so hard. It was actually scaring him to see them so somber. Once the Common Room was cleared out of people completely other than the three of them Percy stalked over. So engrossed were they in their studies that they didn't even notice him and so he got the chance to read the passages of what they were reading.

The Human-Presence-Revealing Spell is the charm which reveals human presences in the surrounding environment by revealing temperatures within a certain distance. The distance depends on the proficiency of the caster and the number of Humans nearby. Humans will generally appear as red, orange, and yellow shaped, while much of the rest of the area will appear as greens and blues. The Spell is also capable of showing off other nearby creatures, magical and non-magical, but this is not a recommended way of detecting creatures as many creatures do not have similar body temperatures to Humans. The targets of the spell will also often time feel as though something is swooping low over them and so this spell does not work well when the caster wishes to remain anonymous.

Percy was startled by what he read over one of the twin's shoulders and quickly switched to the other twin's book. On the page was a large image of a horse quickly shrinking down into a human. It was oddly disturbing to watch and Percy pulled his eyes away from it in disgust not even bothering to read the text. "What in Merlin's name are you reading?"

Both boys jumped in fright and whirled around to stare at him, before turning to face each other. They ignored their older brother completely as they silently discussed something using only facial expressions. Unbeknownst to Percy they boys had actually already discussed this to some degree but were only now coming to an agreement about what to do. If it was possible they grew even more somber.

He watched in concern as their eyes quickly swept over the room. After a few seconds one of them turned to him, pulled him down to his height and whispered fearfully, "We need to show you something bad. It has to be completely secret and you can't confiscate it because then we won't know how to fix it. It's about Ron."

Percy stared at him for several moments before awkwardly craning his head to look at the other twin who was still nervously watching the room, looking for any sign of something. He swallowed and, feeling completely lost and nervous, nodded. The thing was, Percy knew the twins were smart. They never applied themselves in classes unless they were interested, but they were incredibly smart and intuitive, one need only look at the way they set up elaborate pranks and managed to not leave a trace of evidence behind. They learned quickly and well, so if they were afraid of something, it was likely not without reason.

After his short nod the twin released him, scanned the room once more, then removed an old looking piece of parchment. He tapped it with his wand and whispered something. Percy watched in fascination as ink bloomed across the page. The twin quickly flipped it open and scanned the page and sighed with something that was simultaneously relief and not. "He's in his room again," the twin whispered. Instantly the other twin stopped his scanning of the room and turned to look at what Percy was now suspecting was a map, before turning to face Percy.

"This is a map of Hogwarts," he began in a slightly hushed voice, "It shows where everyone is at all times." Percy furrowed his brow as he bent to study the map. It was truly ingenious if it was true. Sure enough, in what was clearly the Gryffindor Common Room, there were three dots each labeled Fred Weasley, George Weasley, and Percival Weasley. He glanced up and realized that for the first time ever he could be sure of which was which. Fred was holding the map and George was the one who had described what it was.

He wasn't able to think further than that as Fred placed his finger on the map pointing out a specific dormitory. Percy studied the area and immediately saw who the twins were worrying over. There in the room were six names, despite the fact that Percy knew there were only five Gryffindor boys that year. Neville Longbottom, Dean Thomas, Seamus Finnigan, Harry Potter, Ron Weasley, and Peter Pettigrew. He stared confused and was about to storm up to the room to see just who it was when both twins grabbed one of his arms.

He glanced down at them and the boys shook their heads. "Sit down, we have more to tell you." He looked between their grim faces before slowly sitting down in a chair they'd pulled up. The boys had been thorough indeed. They'd checked as thoroughly as they could in the room each night, finding no one. That alone should have alerted the intruder if he was watching the boys sleep, but clearly he wasn't spooked or he probably would have stopped. This meant that the intruder was either sleeping there each night and thus didn't notice their searches or was so confident they wouldn't find him that he didn't care.

They'd also tried to identify who it might be, checking the school records for the last seven years to see if there was any student, teacher, guest, or even ghost with that name, but they had found nothing. There were three options as far as the twins could tell. First, the intruder was some kind of spirit, ghost, or poltergeist. They proved to him that they would show up on the map by pointing out that Peeves was currently speeding down the forbidden third floor corridor, quickly followed by Filch. It was a reasonable enough idea, though the twins also pointed out that there was no reason that they could think of for such a being to haunt Ron.

The second was that it was a person who could make themselves invisible. The twins listed off seventeen different ways that they could do so, though each had varying problems with the theory surrounding it, most having to do with longevity or power. For several of them the twins even had ways to reveal the person, though those also had problems which were usually to do with ability to cast or the fact that it alerted the person.

But when it came time to reveal the last reason the twins hesitated. In a sudden case of nerves they both searched the room and the map once more before George finally began to murmur, in the quietest tone Percy had ever heard him use, "Or he could be an animagus." It took him a moment to realize what this might mean but when he did all the color drained from his face. "W-What- Why? How?"

Fred finally spoke up for the first time since revealing that they had a secret about Ron. "It's just- unusual. We don't know how long you had Scabbers, but he's abnormally old. And it's the only option for hiding a person that could plausibly last that long without detection. Theoretically a person can hide that way until they die without having to transform back, regardless of power. Some even do it accidentally when they try the spell out on their own. There are lots of problems for them, they become less human and such, but it would be the easiest way to hide if he's not some form of a spirit."

Percy had gone completely white in horror. He was completely baffled. George decided to answer the other question, the why. "It could be an accident, they could've tried to become an animagus and been unable to transform back. Maybe they did it in secret so no one knew to transform them back. Maybe others knew but he did it on his own, by the time they thought to go looking the rat was gone. They likely wouldn't have even known to go looking for a rat. Or…"

Percy's head shot up from where it had dropped down into his hands. "Or what?" He sounded hysterical and terrified. Fred reached out and rubbed his shoulder, sharing in his brother's feelings completely. "Or", he whispered, "He could be in hiding. For an animagus on the run there would be no better place to hide. A reputable pureblood wizarding family. Especially if no one else knew his form. If he wasn't registered."

Percy felt like sobbing at the idea that he too had slept with a man in rat form for many years. That his younger brother was currently sleeping contentedly next to him right now. He was completely hysterical. "What do we do?" He nearly shouted it and George slapped his hand on Percy's mouth as Fred hurriedly checked the map. After a tense minute or so it was clear that Peter Pettigrew was not coming down to check on the noise and neither was anyone else.

The next hour was spent debating what to do next. Percy wanted to tell the teachers but was eventually persuaded not to until they had solid proof. Yes they had the map but, although there had never been any fault with the map, it was an enchanted item from an unknown enchanter so it'd never be taken seriously.

With that settled they had to decide which way to try to discover proof. By far the easiest way was to do the animagus test, it was the only way they could think of that wouldn't alert the caster until the deed was done. If indeed Scabbers was Peter Pettigrew then they had caught him out, their memories could be used as proof. If he wasn't then there was no harm done.

Percy was so anxious to test it that he insisted they do it the very next morning. The whole night before was awful for all three boys. On their way up to bed each boy checked in on their brother's room and sure enough all they could see were the five boys who were supposed to be there. Percy's heart sank as he trudged up to bed, fear and sadness coursing through him and he was completely unable to sleep.

He was so distracted that he never changed out of his clothes, when he laid down in bed or when he climbed out of it. Instead the moment the sun rose above the mountains he rushed down to the common room and waited for Ron to wake. As he waited and waited the common room filled up and emptied with the normal morning rushes; people waking, waiting for friends, heading down to breakfast, coming back for books or supplies they'd forgotten that they needed for class or to drag out a friend who was oversleeping. Harry Potter and Ronald Weasley were such examples of the latter, Harry dragging Ron down the stairs, each messily put together with only forty minutes to eat breakfast and get to class.

Percy took a calming breath and stalked up to them, ignoring their slightly concerned looks just as he had done all morning with everyone else, and bluntly said, "I need Scabbers for a project. He'll be back by lunch." Ron blinked up in sleepy confusion before slowly rummaging through his disaster of a bag before finally pulling out an equally tired Scabbers who clearly had been nibbling on some of Ron's parchment.

Ron grumbled at this sight and roughly handed him to Percy. "No skin off my back, rat's always eating up my homework. I swear it's like he knows exactly which parchment is notes and which is homework and purposefully eats my homework." Percy swallowed the lump in his throat, hoping slightly that the fact that Scabbers was eating parchment was a sign that he was a true rat and not an animagus.

Harry and Ron stumbled off to breakfast and Percy rushed out and to the nearest empty hall, his grip as firm as possible the whole way. Once alone he Stupefied Scabbers, relieved to see that it worked despite the fact that he'd only practiced it a few times in the past. With that done he felt slightly relieved as he rushed down to the ground floor.

On the ground floor, in the empty classroom next to the Transfiguration classroom Fred had gone completely white and George had immediately rushed from the room looking as though he was going to vomit. Fred had just cleared the map and stuffed it into his bag when George walked in with a slightly annoyed Professor McGonagall in tow. The door close with a click and Professor McGonagall eyed the nervous twins, "Now what is this that you want to show me?"

Before either twin could answer the door open again and Percy walked in with a limp rat in hand. Upon seeing Professor McGonagall his heart jumped in fear. "No… No." Fred just grabbed the rat and placed it on a nearby table while Professor McGonagall watched on in bewilderment. "What on earth has gotten into you boys?"

None of them answered, they all simply pulled out their wands, aimed them steadily at the rat and shouted, "Forma Mutaverum!" Before she could even process what the spell was a blue light shot out of each of their wands and landed on the rat. It was like watching a tree grow, but extremely fast. The passed out rat quickly grew to over a hundred times it size into a huge, poorly groomed man.

She couldn't even think of what to say at the sight of this man who was slowly dozing. Percy was crying heavily as he shouted the stunning spell over and over. Each version was extremely weak but with nearly twenty successive shots at an unsuspecting and only half awake man it quickly overpowered him and he passed out. Percy collapsed and continued to sob in shock at all that happened. Neither of the twins knew what to say as they stared at the man and Professor McGonagall slowly bound the man and floated him to the hospital wing.

Professor Dumbledore questioned each of the boys individually. Each had fessed up to the existence of the map but for some reason it wasn't confiscated. Instead they each received fifty points to Gryffindor, a special services award from the school, a calming draught, and mind healing sessions with Madam Pomfrey. Ron was kept out of the whole affair, aside from the fact that Professor Dumbledore himself returned Scabbers to him, though mysteriously he had regrown a toe and his ear was fixed.