So, I loved the move The Lake House, and this kind of burrowed into my brain after watching that and CoS within the same day. And yes, in my description I stated "it wouldn't be true Marauders fashion if they didn't make one teeny,tiny mistake" because let's face it, they probably didn't always get everything right the first time!
Also: first time really trying the Marauders era, so please don't mind if I miss little bits of their characters.
"Prongs, do you know what you're doing?" Remus asked apprehensively. "A map is one thing, but this-"
"Is pure genius." Sirius said. "McGonagall is catching onto the mirrors, I'm sure of it. This way we can look like we're taking notes in class-"
"But we'll be sending notes instead!" James finished. "Fool proof!"
Remus narrowed his eyes, returning to his book and muttering about their plans. Sirius and James exchanged identical grins and continued their work on the four books.
Peter returned at that moment, an armful of books. "I got the books you asked for- Madam Pince didn't suspect a thing!"
"Perfect! Thanks, Wormy, if we had gone and gotten them, we would have been suspect right away!" James said. "And we couldn't convince Prefect Moony over there-"
Remus huffed loudly.
"This is why it's good we have Wormy as well, no one suspects him, he looks too innocent!" Sirius said, grinning.
"Always delighted, I suppose." Peter said, laughing.
Less than two weeks later, while Remus had been trying to sleep, he was woken by someone dropping a book into his lap.
"Moony, check it out." Sirius said as Remus groaned and sat up.
"What am I looking at?" Remus asked. The others were awake, on their own beds. James was holding another book, and grinning widely.
"Write in it." James said. "Pads, give him your quill-"
Sirius dug through his school bag and handed Remus a quill and a bottle of ink.
"Go on, Moony, write something. Write anything."
Remus narrowed his eyes before uncorking the bottle and dipping the quill. Sirius went to stand by James, looking over his shoulder at the book. Glaring towards them, he wrote:
James Potter is a prat and should never wake a sleeping dog.
The ink glistened and then seemed to be absorbed into the page. Remus looked at James and raised an eyebrow, but he just smiled wider and grabbed his own quill. Sirius gestured to the book Remus was holding. Remus looked down and saw words appear.
PRONGS resents that, seeing as the dog is not actually sleeping, is he?
James, Sirius and Peter were clearly excited- this was a new step up from the map. This was brilliant, and Remus(a little grudgingly) had to admit.
"Alright, it was a genius idea. Now may I sleep?" Remus asked, tossing the book, ink bottle and quill to Sirius' bed.
Alright, so yeah, it's clearly based off of Tommy R's journal. Just less soul controlling.