"The Forbidden Forrest, in the middle of the night, in the freezing cold," said Fred, as he and his brother made their way between the trees. "Remind me again why this is a good idea?"

"Because Filch is up in the school so it leaves the whole Forest free for us to mess around in."

"That's how we were able to get here not why we are actually here. If I wanted to be cold I'm pretty sure I could have done that in the castle."

"That's true, but do you know what you couldn't do up in the castle?" said George turning around and walking backwards while he spoke to his brother.

"Watch you hit your head on that branch?" said Fred, nodding behind his brother.

"What? Ow," said George, who had turn around in time to smack his forehead off the low hanging branch. The cold weather made it hurt much more than it would have normally. He rubbed his head with his hand. "No, I meant what we couldn't do up at the castle is watch the Centaurs take part in their annual Winter Solstice Ceremony. Apparently it's pretty amazing."

"Pretty amazing?" asked Fred sceptically. "What does it involve?"

"Well there's a big fire…"

"That'll do for me," said Fred, rubbing his hands together.

The twins continued to trek into the dark of the forest. The school had long disappeared from their vision, although the thickness of the trees had more to do with that rather than the distance they had travelled. Both boys had their wands illuminated to light the way as well as to potentially ward off any creatures that might be out looking for a night-time snack. Most people who ventured into the Forbidden Forest tended to employ a cautious approach and tried their best to remain silent. The twins were not most people.

"Hogwarts, Hogwarts, hoggy hoggy, Hogwarts, teach us something pleaaaaaasssseeee," bellowed Fred at the top of his voice.

"Warty," said George, cutting his brother off mid-flow.

"What?"

"It's 'Hogwarts, Hogwarts, hoggy warty, Hogwarts'," said George, correcting his brother.

"Are you sure?" said Fred. "I always thought it was hoggy hoggy."

"That would make no sense," scoffed George.

"Hogwarts, Hogwarts, hoggy warty, Hogwarts," muttered Fred quietly to himself. "No, it just doesn't sound right."

"You mean 'hoggy, hoggy' sounds right?"

"Fair enough. Quick question George," said Fred, stopping in his tracks. "Where in Merlin's Beard are we going?"

"Er… I'm not actually sure. We were supposed to just head directly east from the castle, and we'll pass a small stream, which we have, go through one large clearing, which we did, and just after two large fallen trees we should reach another clearing and that's where the ceremony will be taking place," said George, trying to recall the directions.

"How do you know all this?"

"It was in Enoch's letter," said George. He spotted the frown on his brother's face. "Did I not tell you we got a letter from him?"

"No, that must have slipped your mind," said Fred, shaking his head.

"Oh, well he was the one that suggested we take a look at the ceremony. Here you can read it for yourself," said George, reaching a hand into his pocket and taking out a folded piece of paper.

"You got this like last week," said Fred, as he read the letter.

"I've been busy," said George, shrugging.

"Well it sounds like a good idea, bit of dancing, some music… ooo Centaur food. I wonder what that is," said Fred, reading on. There was something nagging at the back of his mind which he couldn't quite place. He finished the letter and continued to stare at it for a while.

"Good grief, and I thought I was a slow reader," muttered George.

"I've finished reading it you idiot, there's just something about it that doesn't seem right," said Fred, looking for any clues as to what was unnerving him about the letter. His eyes were drawn to one word on the page in particular; it was the word 'definitely'. "Definitely, definitely. Here, look at the spelling of the word definitely. Does it seem wrong to you?"

"No, that's how you spell it," said George, examining the word under wandlight.

"That's my point. How many letters has Enoch sent us over the years? How many times has he spelt 'definitely' correctly? It's not just that word either, it's loads of them; experience, familiar, finally. They're all spelt correctly. And remember his last letter? It warned us that he was in trouble but this one doesn't even mention anything to do with that," said Fred, frowning. "There's no way he wrote this."

"Well I had hope you would have got further into the forest but I suppose here is just a good a place as anywhere," said a voice behind them.

Fred and George spun around quickly. Standing about thirty foot behind them was a figure dressed in dark robes. It was difficult to make out any more since the man had a cowl pulled up over his head while the light from his wand was too bright to see passed.

"Who are you?" demanded George, pointing his wand at the figure.

"Who I am isn't important," said the man.

"What are you doing here?" asked Fred.

"Me? I'm just taking a stroll through the forest," said the man in a casual manner. "I thought I might take in the Centaurs' Winter Solstice Ceremony. Apparently it's pretty amazing."

"How did you know about… wait, it was you wasn't it? You wrote the letter," accused Fred.

"Guilty as charged," said the man, laughing slightly.

"Why?"

"Well your dear uncle Enoch was proving to be a rather awkward fellow to pin down. So I thought to myself 'what's the easiest way to capture something?' And I realised the answer was to make sure you have the right bait. And now I do. You two."

"What do you want with Enoch?" asked Fred. The man had slowly begun walking towards them so the two boys were trying to back away without tripping over in the dark.

"Easy. To kill him."

"What's he ever done to you?" snapped George, trying to sound far braver than he felt.

"Nothing, well apart from some choice insults when I thought I had him cornered a few months back. I'm not killing him because I want to; I'm killing him because someone wants him dead."

"What's the difference?" asked Fred, stalling for time while he thought of a plan of escape.

"I'm not a common murderer dear boy; I'm a highly skilled assassin. Any idiot can be a murderer. Assassination is delicate and precise art form when done correctly. And I am one of the best when it comes to doing things correctly."

"Look, whatever you are being paid…" began George. The man started to laugh.

"You'll double it? I doubt your pocket money would amount to much."

"Shows what you know. We don't even get pocket money," said Fred, sneering at the man. He glanced over at his brother who was now looking at him and shaking his head. "What? It sounded good in my head."

"What do you think we should do?" whispered George as quietly as he could.

"I think we should do what we always do," said Fred, shrugging.

"Fair enough."

"So are you going to be good boys and come quietly? Or is this going to turn ugly?"

"Hey, we're just kids, we don't want any trouble," said Fred, holding out his hands up. "NOW!"

"Pertificus Totalis!" shouted George, aiming his wand towards the man.

"Furnuculus!" Fred fired his own spell at the target.

Neither boy waited to see if their spells hit their mark. Instead they were already off running through the darkness trying their best not to trip. They kept running as hard as they could until they came to a small clearing.

"Wait," puffed George, slowing to a stop. Both he and his brother had extinguished the light from their wands but still kept them raised just in case. "Where are we? Which way is the school?"

"I think it's…" Fred tailed off as he looked around. "I have no idea."

"Brilliant, we're lost with a nutjob after us."

"And for once it isn't Filch," said Fred. He pointed towards one side of the clearing. "I say we go this way."

"Why that way?"

"It's as good as any other way and it'll take us in the opposite direction of the nutjob," reasoned Fred.

"Should we try and get the attention of someone in the castle? Like sending up red sparks or something?"

"Who'll see it? Apart from the nutjob."

"Well that was an enjoyable little jaunt through the woods," said the voice of the man who was now emerging from the trees. He held his wand lazily in one hand and if he hadn't previously indicated his nefarious intentions, it wouldn't have been out of place to assume he was just enjoying a leisurely nightly stroll through the forest.

"Expelliamus!" barked George quickly. His heart leaped as the man's wand shot forward before he could grip it in time. The boy caught it in his spare hand and held it aloft triumphantly. "Aha!"

"Nice one George," beamed Fred. He turned to address the man. "Who's the tough guy now then eh?"

"Oh I don't need a wand to be able to take care of a couple of children," said the man. His hand reached inside his robes and pulled out a long sharp and slightly curved knife.

"Hang on, you only have a knife, we're the ones with the wands," said George as the man began to slowly walk towards them.

"I'm quite aware of that. My point is it doesn't matter," said the man, continuing his approach.

"Stop right there or we're going to have to stop you ourselves," said Fred, raising his wand in a threatening manner.

"We mean it," stated George once it became apparent that the man had no intention of stopping. He looked over at his brother.

"We warned him," said Fred, shrugging.

The two boys aimed their wands and each fired off a spell which hit the man square in the chest. Their celebrations were short lived when it became apparent that despite being struck by both spells, neither of them seemed to have had any effect on the man. Overcoming their initial surprised they once again fired off a spell each, and once again the man suffered no visible ill effects. Desperately trying one last time the twins fired off a whole barrage of spells one after the other in a non-stop attack that lasted about a minute and left them slightly out of breath when they finally stopped. The man was still standing in the same place and was now laughing at the ineffectual attacks.

"How?" it was the only word George could manage to force out against the rising panic he was now feeling.

The man lifted his hands slowly up to the cowl shadowing his face and pushed it back. Fred managed to stifle his sharp intake of breath but George was unable to stop himself from swearing. The man was no man, he was… something else.

Although he had similar features to a human; two eyes, nose, mouth, they were not completely normal. The eyes were perfectly round, much further apart than normal and seemed to be moving completely separately from each other. His nose was extremely thin with one nostril protruding on each side rather than at the bottom. His mouth held two rows of sharp looking teeth and a thick black tongue that matched the colour of his lips. His skin was made up of tiny green scales which, along with the rest of his features, made him look like an oversized chameleon.

"What is that?" said Fred, not entirely sure if he want to know the answer.

"Some kind of weird lizard man thing," ventured George.

"I'm a Kosa," said the man. A look of distain had crept onto his face after George's comment.

"I would say it's a pleasure to meet you A-Kosa, but you know the whole trying to kill us thing sort of gets in the way of being nice," said Fred sarcastically.

"I'm not trying to kill you, well not yet anyway," said the man, smirking. "And my name is Valek. Kosa is my species."

"Is that supposed to mean something to us?" asked George. The twins had now more or less backed away the entire width of the clearing as they tried to keep some distance between themselves and Valek.

"I'm not surprised you don't know about my kind. As there so few of us left not many do. In fact I think I could very well be the last of my kind," said Valek, shrugging. "We were officially registered as extinct about a decade ago."

"Well if this is how your people acted, I doubt they'd be missed much," said Fred. He looked over his shoulder to try and gauge how far it was to the tree line.

"Yes, we were never popular with you wizards. It could have been down to our different social structures, our desire to increase our political power amongst the other magical beings, or even our habit of accumulating wealth. But personally I think it was down to two very simple factors. One; we're naturally immune to magic, and two; we just really like killing things," said Valek. His black tongue snaked out and licked his lips as he smiled.

"How far away are the trees? I reckon we could lose him in there," whispered George.

"About another twenty foot or so," guessed Fred. "Just keep him talking a little longer and we'll be there."

"I also happen to have very good hearing," said Valek, tapping the side of his head. "This is the last time I'll ask. Give yourselves up, or I will just kill you."

Before either Fred or George could reply there was the sound of snapping twigs and rapid footsteps approaching from one side of the clearing. Valek had heard it too and stopped in his tracks with the curved blade held out in front of him. The twins were unsure where to aim their wands since there was a very good chance that whatever was coming could be just as dangerous as the Kosa. The sound grew louder and louder. They could make out something large and white making its way through the trees towards them. The creature leaped over a thicket of thistles and into the clearing. At first Fred and George thought it was just a horse which had escaped from the school stables but as it raced through the clearing they saw a single horn protruding from its forehead. It was the first time either of them had seen a unicorn and despite the situation they still marvelled at its beauty as it raced threw the glade towards the trees opposite.

Valek snarled and began to move towards the twins again before a second sound stopped him once more. Fred expecting another unicorn started to back away towards the tree line while pulling his brother along with him by the arm. George tapped him on the shoulder and pointed. Following his brother's gaze Fred saw towards what he was gesturing. It wasn't a unicorn. It was a dark hooded figure.

The figure turned to look at the twins. Although they couldn't make out its features both of them felt a chill run through their veins as its eyes fell on them. It slowly turned to look at the Kosa. Valek let out a long low pitched hiss and bared his teeth. There was a brief moment where when it looked as though he was about to attack the newcomer but instead gradually began moving away always making sure to keep the creature in sight.

"What do you think?" whispered George, trying to keep his voice as low as possible.

"I think that whatever that is," said Fred, pointing at the strange creature, "it's dangerous enough that Valek is scared of it. And he's immune to magic."

"Do you think it's friendly?" George only had to look at his brother to guess his answer. "Fair enough, there's no need to make that face. Let's get out of here."

The twins backed away to the safety of the tree line before turning tail and running as fast as their legs could carry them. They didn't dare look behind and both barrelled forward through the trees and the undergrowth leaving the clearing far behind them. After a good few minutes of running and several near falls they both finally stopped to catch their breaths.

"What was that thing?" said George, gasping for air.

"I haven't even heard of a Kosa before. Have you?"

"No, not Valek. The other thing."

"No idea. It's the Forbidden Forest. There are hundreds of things in here that are far more dangerous than Valek," said Fred, waving his hand in the air.

"I really wish you hadn't said that while we are standing alone in the middle of the Forest."

"Why not?"

"Because its one of those things you just don't say. Like 'everything will be fine' or 'nothing can go wrong' or 'this'll be the best Christmas those orphans will ever have'. The moment you say something like that then something bad always happens. And saying that there are hundreds of things in the Forest that are far more dangerous than an assassin who is immune to magic who wants to kill us instantly means that something is about to come out of the trees and attack us," said Fred, as his voice got more and more high-pitched. He held his wand out expecting an immediate onslaught from the darkness.

"So how long are we going to wait to be attacked?" asked George, after a few minutes.

"Well these things normally happen straight away as far as I know," said Fred, frowning.

"Right and since we weren't attacked straight away?"

"We're probably safe," said Fred, relaxing, although he still kept out his wand.

"Plonker," said George, shaking his head. "Any ideas where we are?"

"None. I think we might have moved even further away from the castle," said Fred. He looked up at the trees that surrounded them. "Maybe we could climb one of these and try and spot which way we should head."

"Good luck with that," said George, slapping his brother on the back. "I'll wait down here."

"Right," said Fred. He scratched his chin and looked at the nearest tree thoughtfully as he worked out the initial route he would climb.

There was a snap of a twig in the dark.

Fred span around and grabbed for his wand just as something shot out of the shadows and knocked him over onto the ground.

"Fred!" shouted George, pointing his wand at the creature.

"Fang! Bad boy!"

"Hagrid?" said George, as the school's groundskeeper came out of the darkness. George looked down at his brother and he realised the creature he was about to attack was actually Hagrid's pet dog which was enthusiastically licking Fred's face.

"What are you two doing here?" demanded Hagrid.

"About to drown," said Fred, covering his face as best as he could from the dog's slobber.