A/N: This is what I think likely happened when Sirius tried to get Snape killed by telling him how to get near Lupin under a full moon. Set in Marauder's/MWPP era, in their 6th year. Lily's POV.
I thought this was one piece of history that needed some filling in. I hope I'm accurately representing the characters and their (possible) relationships at this time. Please read and review.
I should also note that I've done a slight tweaking of The Most Ancient and Noble Black Family Tree. So I guess the story now falls under the category of A/U (alternate universe). But it doesn't widely affect the plot, and it is only a minor character (who I'm starting to quite enjoy writing!) that gets tweaked into the story, so I hope I am right in believing that the purists will forgive me? ;-)
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James and Peter whipped around from where they had been having their conversation. Lily noticed Potter was holding some silvery material bunched up in his hand.
"Tibby! Evans!" He was surprised enough that he hadn't lowered his voice to speak to Lily, as he usually did.
"Remus Lupin is a werewolf?" said Tibby.
"Oh my goodness." That was all Lily could say. It all makes sense now! That's why my fellow Prefect is always looking ill, why he misses classes, why... Her thoughts were interrupted by Tibby speaking again.
Tibby had gotten up, her book falling to the floor. "How? How?"
"Look -- Tibby, look. It's not what you think!" James was trying to make up for the mess he had created.
"Not what I think? James, in case you didn't know, a werewolf is a very dangerous creature --!"
"Keep your voice down!" whispered James.
"Now, I know this is Remus we're talking about, but you can't blame us for being a little bit alarmed that he's a werewolf! He's dangerous no matter which way you look at it!"
Peter looked nervously at Tibby, Lily, and James. "It's not as bad as that, really." said Peter in a would-be calm voice. Peter had always seemed a little scared of Tibby, or so Lily had observed.
"Does Dumbledore know?" said Lily, getting up to stand beside Tibby.
James seemed to be fighting something within himself for a moment, then sighed. "Yes, he knows." he said angrily and scratched his messy head of black hair. "And he has put in place -- certain precautions -- so that Remus can't hurt anyone when he transforms. And that's the only time he can hurt anyone."
"So...so he's not dangerous?" Tibby said slowly.
"No!" said James.
"This is so wierd," Tibby plopped herself down on to the couch by the fireplace near where she had been standing. "I always thought that werewolves were dangerous, and ... and bad," she added lamely. "But Remus is --"
"But Remus is not." James finished for her, as if to press the point.
"Well, no!" Tibby replied.
"Look," started Peter "you really can't tell anyone."
"That's right. You can't. It was stupid of us to even be talking about it so openly...but I guess we've been a bit careless." James' gaze went from the two girls to the fireplace, he was really ashamed of himself for letting it slip.
"I --" Tibby was still apparently having trouble grasping the concept of a good werewolf: being brought up in a wizarding family like her's she probably grew up believing werewolves were evil, instead of not knowing they existed, as Lily had. "Of course I won't. Neither of us will."
"Yeah, " chimed in Lily. "It's not your secret to tell, let alone ours."
James groaned and leaned against the fireplace mantle. "I don't know how I'm going to tell Remus I spilled his beans for him. I'm such an idiot."
Lily shocked herself by thinking the opposite for a moment. But before it had occured to her to relay that in words Tibby said "Yeah, well, we already know you're an idiot, so no suprises there."
James laughed dryly. "Oh, thanks Tibby. You should use that as a pep-talk for our next match." Tibby played on and was captain of the Gryffindor Quidditch Team, so she and James were somewhat friends. She dissaproved of his bullying behaviour as much as Lily did, but for the sake of the team Tibby and James managed to be friends, most of the time.
"But seriously," continued Tibby, ignoring the sarcasm in his comment, "what kind of precautions are there to prevent Remus from biting someone? What if he got loose by accident?"
James and Peter exchanged a look. Peter said to James "It can't hurt telling them now, I think..."
Potter sighed again. "Well, every night of the full moon he goes to a house in Hogsmeade where he's locked up and can't hurt anyone."
"But how does he get there before it's dark? It takes a while to get to Hogsmeade...what does he do in winter when it's dark even before dinner?" said Lily.
"Well, there's a tunnel that starts in the grounds here at Hogwarts. Besides, the darkness doesn't really matter. It's when the moon is up that he's transformed."
"Really? Where is the tunnel?" asked Tibby curiously.
"At the base of the Whomping Willow, that way nobody that doesn't know how to get past it can go near Remus when he's transformed. Pretty clever of Dumbledore, really." added James.
"Oh...so that's why --" Lily gasped in horror. "Oh my God! Snape!" said Lily, jumping up.
"Snape?" said James in confusion. "What's he got to do with anything?"
"Sirius!" she said this time to Tibby, who didn't understand her cryptic remarks any better than James did.
"Lil," said Tibby slowly, "Are you going to start making sense soon?"
"Listen!" she exclaimed, turning to James, "When I was in detention I heard Sirius telling Snape that all he had to do to get past the Whomping Willow was to prod a knot with a stick! Don't you see?!"
James' eyes widened in horror. "Snape's going to try to get in! He doesn't know that Remus is a werewolf!" he turned to his friend, "Peter! The map!"
"Oh. Oh...shit, oh shit, this is bad." Tibby was muttering under her breath.
Peter looked quite bewildered. Then looked as if he got it and started rumaging in his pockets, eventually producing a crumpled piece of paper.
James grabbed it from him, pointed his wand at it and said "I solemnly swear that I am up to no good."
"What the hell --" started Tibby but stopped when she and Lily saw ink lines speading all over the paper until they were recognizable as a map of Hogwarts!
James looked at it for only a second before he dropped it and bolted through the portrait hole, disappearing before anyone could say anything else.