Chapter 1.

It was a week before Christmas and most of the Gryffindor students were lounging around in the Common Room, completing some last minute homework before the holidays, or just chilling.  Normally, a group of 6th year boys would be in the middle of the Common Room, stirring up some sort of commotion, but on this evening they were in their dormitory instead, conspiring behind their closed door.

This group of boys was infamous throughout the Hogwarts population – two of them were tied for the position of 'most detentions ever served by a single Hogwarts student', and the other two weren't far behind.  Indeed, one of them, by the name of Peter Pettigrew, was running late for a detention that he was meant to be doing that evening.

The other three boys chuckled as Peter noticed the time and ran out of the room as quickly as his short legs would carry him.  Two of them had bet on how many minutes would pass before Peter realised that he was running late.

"Hand it over mate." said James, looking expectantly at Sirius.

Sirius slid to the end of his bed and, hanging over the side, rummaged around in his trunk for his money bag.  He fished out three galleons and threw them to James, who caught them easily despite the fact that they were aimed at his head.

"Thanks for that," said James.  "Now I've got enough for that new screaming yoyo they're selling at Zonko's."

Sirius rolled his eyes and slid back up to the other end of his bed where he'd been lying on his stomach, reading a book on charms.

"You said you weren't going to do that anymore." said the third boy, Remus Lupin, quietly without looking up from his own book.

"What?  Go to Zonko's?" asked James innocently.

"Betting on Peter." Remus corrected in a would-be stern voice.

"Aww… Come on Moony!" whined Sirius.  "It's just a bit of fun!"

"Yeah, it's not like it's hurting anyone, right?" added James.

"If you actually told Peter when he was late he wouldn't get points taken off for it." Remus informed them with a sigh.

"So what?  It's only 5 points – it's not like it really matters!" James exclaimed.

"Hey," interrupted Sirius.  "Check this out – I figured out how to do that charm you asked about James."

James rolled off his bed and walked over to see where Sirius was pointing at his book.

"It's a combination of a simple timer charm and a variation of the banishing charm." Sirius said in a scholarly voice.

James nodded.  "Looks easy enough.  You wanna give it a go tonight?"

Remus prevented Sirius from replying by talking over the top of him.  "What are you two planning?"

Sirius and James tried to look innocent, but failed miserably under a stern look from Remus.  Sirius figured he'd better explain.

"It's a charm that'll send the Slytherins zooming into the middle of the lake at whatever time we choose – say, during classes tomorrow.  Because it works on a timer, we can cast it tonight, then make sure that we're somewhere that the teachers can see us when it goes off tomorrow.  That way, we can't possibly get in trouble for it!"

Remus rolled his eyes.  "You not seriously expecting to pull that off, are you?"

"Sure, why not?" asked James, thinking that Remus was going to point out some fatal flaw in their plan like he usually did.

"Because, for a spell that strong, you'll need at least three people to work it."

James and Sirius grinned and showed Remus the spell.  All three of them pulled out their wands, stood together and concentrated on the Slytherins as they muttered the incantation.

"Ablegatio!"