"We're idiots," Fred said as soon as they were out of earshot of the girls.

"Actually I thought that went rather well," said George. "We found something about Agatha's uncle for her-"

"She has a cat," Fred said.

"What does that have to do with anything?"

"Animals show up on the map," Fred said. "If Agatha has cats and she named one of them Peter-"

"-it would automatically get her last name and show up on the Map as Peter Pettigrew? I'm not sure I buy that."

"But it would explain so much," Fred said. "If Peter's a cat then of course none of Percy's roommates think twice about him sleeping on Peter's bed. And Bill can't be expected to know everyone's pets' names."

"Agatha said her kittens are too young to be giving away just yet," George said. He would have added that she should have mentioned if one of her kittens had already been claimed by Percy Weasley, but he knew that Fred could concoct some almost-plausible explanation for that.

"Her brother could have had a cat that had older kittens," Fred said, "and Percy could have adopted one-"

"But then you'd think the cat would be Peter Weasley." And then George realized the really glaring hole in Fred's theory. "Besides, Percy already has Scabbers, so unless Peter ate him-"

"That would explain why Scabber's hasn't shown up on the map," said Fred. "The only other way to figure it is if Peter was Scabbers, and that-"

-makes way more sense than Percy suddenly, without anyone noticing, acquiring a kitten."

"I suppose someone probably wrote a spell that can turn a person into a rat," Fred said. "Beats me why they would want to-"

"-because it would be so much easier to just kill him," George finished. "How's this for an idea, Peter Pettigrew was one of the people who made the map. After a falling out with his friends he bought a whole bunch of rats, named them all Peter Pettigrew and set them loose in the castle so that no one could use the Map to track him."

"Do you really think that's more likely?"

George shrugged. "I don't know where Scabbers came from, but I'm sure Percy had him before he came to Hogwarts."

"You're not helping your case." Fred didn't have anything else to help his own case so he left it at that, knowing that, if there was anything he was missing, George would think of it.

"I think it comes down to how Peter died," George said. "If they buried him, if he wasn't missing and presumed dead or something like that, then I don't see how he could be Scabbers. I suppose he could be a relative also named Peter-"

"He's Junior," Fred said with more confidence than he felt. "Some Death Eater felt bad about killing a kid, so they turned him into a rat instead."

"Because they knew a spell to turn someone into a rat off the top of their head," George said. He paused for a second, realizing for the first time the full implications of tuning someone into a rat. "I think turning someone into a rat would be crueler than killing them outright. They'd probably get eaten by a cat, or poisoned, or starve to death. And they'd have a rat's brain wouldn't they, so would they think they were a rat or-"

"It wouldn't be that hard to find food," Fred said over George's continued theorizing. "Rats eat the same things as people."

"But people normally shut their food up so that rats can't get into it." George chewed the inside of his lip. "I suppose they could chew their way through wood eventually. If they thought of it soon enough."

George could see in his mind's eye, a small lump of fur gnawing plaintively at a the door to a pantry only to lapse into unconsciousness before reaching the food.

Fred turned a slightly greenish color. "We should probably look up what happened to Peter Pettigrew before we speculate any more."

George nodded. "And figure out how turning someone into a rat works. If it doesn't match up with how he died-"

"-or if it leaves the victim with the mind of a human inside of a rat-"

George raised an eyebrow, silently asking for Fred's reasoning.

"If someone turned me into a rat, the first thing I would do is knock over a bottle of ink, write 'I'm really a human, not a rat. Please turn me back.' and sit next to it," said Fred. If he was honest with himself he would panic a bit first, but that didn't really count.

"That'd be a wicked practical joke," George said. "How do you know he hasn't done it already and had it brushed off as a joke."

Fred burst out laughing.

"So we would have been blamed for it if he'd done it at home," George said, "but once Percy got to school-"

"-all he'd have to do is keep doing it and eventually McGonagall would have had to check."

"Unless there's no way to tell the difference between a rat and someone transfigured into one," George said, although he did not really believe that was the case. There were all sorts of spells to reveal magic and negate other spells, he'd heard Bill going on about them while extolling the virtues of cursebreaking to Mum and Dad in an attempt to show that it wasn't really that dangerous of a career.

"Why wait until he's a Hogwarts?" Fred asked. "Mind you, if I had to end up as an animal, life as Percy's pet rat wouldn't be too bad-"

"-but you wouldn't want it for any longer than absolutely necessary."

"And if Scabbers had tried that at Hogwarts, we would have heard about it. Percy never would have shut up about it, you know how he is."

George opened his mouth, closed it, and opened it again before speaking. "I know. I know. It's just-"

"-you've caught the idea and now it won't leave you alone." Fred tried not to look too smug about it. "That's how I've been about Peter Pettigrew in general all week. Maybe you're on to something."

"Nah," George said. "I think it makes me more nervous than anything."

"It is a bit creepy," Fred agreed.

George checked his watch. "If we're quick, we can make it to the library and see if Pettigrew's death made the Daily Prophet before curfew."

"We'd have to skip dinner," Fred said, entirely ignoring the fact that George had already eaten. "Unless you fancy sneaking down to kitchens after curfew and then back up to Gryffindor Tower-"

George handed him the piece of steak-and-kidney pie that he'd packed in his pocket.

"Thanks," said Fred. He took a large bite out of it and spoke as he chewed, "I suppose this means that you expect to go to the library tonight."

"I would make you eat some celery too-" George took a stick out of his pocket and waved it at Fred. "-but Madam Pince will chuck us out if she catches you eating in the library."

"I'll be done by the time we get there," Fred said through another mouthful of steak-and-kidney pie. He snatched the celery out of George's hand and took off running "And I can eat the celery in that time. Bet you a sickle."

"You're on," George said, as he ran after Fred. He wasn't likely to win, no with Fred having a head start, but George currently had five of the six sickles the twins had come to Hogwarts with, so it didn't really matter.