Four Times the Weasley Twins should have realised (and one time they did)
The Burrow, the summer after Fred and George's second year
"Fred?" said George.
"Yes, George?" said Fred.
"Are you bored?"
"Yes." The twins let out simultaneous sighs. After so many months in a castle with almost unlimited potential for mischief, the Burrow just didn't cut it. Even teasing on Ron and Percy could only amuse them for so long. The day was hot, and everyone in the house had retreated to their own rooms. Fred and George were lying on their single beds, staring at the ceiling and lazily fanning themselves. Percy's rat Scabbers was snoozing on the dresser.
"I miss Hogwarts," said Fred, echoing his twin's thoughts. "I wish..." he sighed again, unable to voice his thoughts.
Suddenly George sprang up, a grin splitting his face in two. Rummaging around in the debris that littered the floor of their room, he exclaimed in triumph and turned to face Fred, brandishing a first year Charms text in his hands. "A cure for your homesickness, brother of mine. Or should I say..."
"...schoolsickness!" they chorused together. George opened the book and extracted a dog-eared, blank piece of parchment. They both reached for their wands (almost useless during the summer, thanks to Ministry regulations, but effective in this instance) and chanted together, "I solemnly swear that I am up to no good."
If they hadn't been so engrossed in the spreading lines of ink upon the parchment they may have noticed Scabbers' abrupt awakening, and heard his surprised squeak. As it was they didn't notice him until he literally jumped off the dresser and started chasing his tail.
"What on earth... the rat's gone mental," Fred exclaimed.
"What do you expect? It is Percy's rat," George replied.
"True."
The twins shrugged and went back to speculating on what Hagrid was doing in the third floor corridor.
TWO DAYS LATER
Fred burst into the kitchen where his twin and other family members were eating breakfast. "It's gone!" he yelled, before tripping over his own feet and falling flat on his face.
"Fred! Are you all right?" exclaimed Molly Weasley worriedly.
"What's gone?" asked Ron.
Fred got to his feet, and waved away his mother who was trying to heal a graze on his nose. "Moony's parchment," he said urgently. George gasped. In the blink of an eye both twins had left the kitchen and could be heard pounding up the stairs.
"Nutters," muttered Ron. Molly sent him a disapproving look.
By the end of that day the twins had searched most of the house. Only their parent's room and the attic remained. Agreeing that their mother was far scarier than the ghoul, they boosted themselves into the cramped, dusty space beneath the roof. Combing through years of family heirlooms, broken furniture and other assorted junk, they finally hit pay dirt.
"Aha!" cried George. In the corner of the attic was a nest made, as far as the twins could tell, from old rags, twigs, a Hogwarts school tie and scraps of chewed on paper. Lining it was the Marauder's Map. And sitting on top of it was Scabbers.
"Shove off, you stupid rat," said George, and liberated the parchment from the nest. Scabbers reared back on his hind legs and for a second George had the crazy idea that he was going to bite, but instead he turned and scurried away.
"We're never letting this out of our sight again," vowed Fred. "Stupid Scabbers."
"Agreed," said George. "Out of all the pieces of parchment in the house, the rodent had to have this one. Makes me weep, it really does."
Hogwarts Common Room, end of Harry's third year
"I don't believe it," Lee Jordan raved. "A werewolf! All this time, in the school, teaching us Defence! I knew Dumbledore was batty, but this is too much."
"Indeed," drawled Fred.
"Totally crazy," agreed George.
"One might even say..."
"Complete lunacy!" they yelled together, making a first year behind them jump. They set about laughing at their own pun, while Lee paused in his outrage long enough to whack them both up the back of the head.
Grimmauld Place, summer before Harry's fifth year
Molly's shriek echoed through the house. Bouncing along corridor and up stairwells, it reached the ears of the twins, who promptly Apparated downstairs to see what all the fuss was. What they saw was their mother scolding a large black dog who, as far as he could, was trying to look repentant. From their vantage point they could see two large dusty paw prints in the small of their mother's back.
"... don't know where you get the idea that I need a good fright! As if there isn't enough of that going on outside. And I don't know how you managed to sneak up on me with those great heavy paws, but I don't want you doing it again, understand? And as for the example you're setting, well..."
The twins grinned. Sirius was always good for a laugh. He was a true kindred spirit.
Room of Requirement, DA meeting
"Nice rack," George said.
Hermione spun around, spluttering. "What did you say?" she demanded.
"Harry's Patronus," Fred said calmly. "Nice rack..."
"... of antlers," George finished. "Do you think he's..."
"... compensating for something?" they finished together, cackling.
Hermione gave them a dirty look. "Boys!" she exclaimed.
Weasleys' Wizard Wheezes, one year after the final battle
"I'm glad you got the shop back open," Harry said. He and George were sitting in the storeroom for George's lunch break, munching on some sandwiches. "Ron tells me he might be coming to work here."
"Yeah," agreed George. "We need an extra pair of hands, and as much as I hate to admit it, an extra brain. Don't tell him I said that," George warned.
"Of course not," Harry laughed.
"And of course, it means we won't have to move the apostrophe," George said brightly.
Harry nodded. Other people may have been disquieted by George's veiled reference to the loss of his twin – his second half – but Harry wasn't the Master of Death for nothing. "Keeping it in the family is good. I'm sure the Marauders would have approved."
"Ah, the Marauders," George said, with a wry smile. "You may have provided the money, but they provided the inspiration. I wonder if we could find out who they are one day and thank them."
Harry nearly dropped his sandwich. "You- you don't know? But I told you." Harry frowned, searching his memory. "I must have told you," he said less certainly.
"Harry," George said, with deceptive calmness, "are you telling me that you know who the Marauders are?" He seemed to be on the verge of hyperventilating.
"Yeah," Harry admitted. "I've known since my third year. "
"Who, Harry," George nearly shouted. "Who!"
"Well, Moony was Remus," Harry said. George's eyes nearly bulged out of his head. "He got his nickname from the werewolf thing, obviously. And the other Marauders were all Animagi so they could help him during the full moon. That's where they got their names."
"But that would mean..." George shook his head, trying to put it all together. "Sirius was Padfoot?"
"Yep," Harry said, starting to enjoy George's surprise. "And Wormtail was Peter Pettigrew."
"Wormtail... so what would his form be? A snake?" George guessed.
Harry stared at him in disbelief. "You mean Ron never told you..." Seeing the impatience in George's eyes, he continued. "Wormtail was a rat. Ron's rat, Scabbers."
"No," George said flatly.
"Yes," Harry insisted.
Harry watched as George struggled to come to terms with this. He thought he would have to wait a few minutes, but George's quick mind had already moved on to the last name on the list.
"So Prongs was... your Dad," he said softly.
"Yeah," Harry replied. "He was a stag, like my Patronus."
They sat in silence for a bit, finishing off the sandwiches while deep in thought. Suddenly Harry laughed. George looked at him curiously.
"You wanted to thank the Marauders," Harry said with a grin. "Well you grew up with one of them for a pet, was taught by another, lived in the house of the third and finally, this magnificent shop," Harry waved his hand at their surroundings, "was financed by the son of the last. I think you've probably thanked them all, at one time or another, even if not directly."
George looked at Harry, and bounced up out of his seat. "You're right, Harry," he said. "Brilliant! I can't wait to tell..." Suddenly George froze, and then flopped back in his seat, all of his energy leaving him. Sitting there he looked washed out, like an old piece of clothing that had seen better days and should have been retired long ago.
Harry's heart ached, for a moment, at the magnitude of his loss, at learning to speak in 'I' instead of 'we'. But then he remembered a conversation with a Headmaster, and Kings Cross, and a stone lying somewhere in the Forbidden Forest. He put his hand on George's shoulder.
"He knows," Harry said, softly but certainly.
Somewhere
"... and that, my friends, is why to this day Justin Finch-Fletchly cannot look at a kipper without twitching," Fred finished triumphantly. The other people seated around the table roared with laughter.
Wiping tears of laughter from his eyes, Sirius lent forward. "Ok, how about this. One time, in first year, James and I were in detention..."
He knew.
