Outside, people are going about their business on Frosty Avenue. Friends are chatting on Kris Kringle Drive. A gang of hoodies are slouched against the candy-cane striped streetlights on Santa Claus Lane, having just emerged from the Christmas-themed McDonald's. Everything in North Pole is Christmas-themed. Itis Christmas Day 365 days a year. The decorations are always up. It never stops being Christmas here. Never. Wherever you are in the world, if you write a letter to Santa, and address it simply "Santa, North Pole", your letter will most likely end up in this tiny Alaskan town.

Actually, specifically, your Santa letter will end up right here, in this smoke-filled scratchcard and cigarette shop. It's late October, and boxes of them are already piled up on the counter near the fruit machine. They're automatically forwarded here from the post office. I pick up an envelope at random. It has only one word scrawled on it, in a child's handwriting: "Santa." It's postmarked Doncaster.

I get talking to Debbie who works here, selling scratchcards to the gamblers. Debbie is herself achain-smoker, a blousy strawberry-blonde with a tough, good-looking face. She says she can frequently be found alone in here in floods of tears having opened yet another heartbreaker. "Just before you got here," she says, "I opened one that said, 'Dear Santa. All I want for Christmas is for my mother and father to stop shouting at each other.' I just fell apart."

"We get a lot of, 'Could you bring my father back from Iraq?' " says Gaby, the shop's owner.

I open another one at random. The kid wants an Xbox. And then I feel terrible that some child wrote to Santa, posted it off into the great unknown, and who opened it? Me. Non-magical me.

Debbie answers as many Santa letters as she can, whenever she gets a break. She writes back using her elf name: Twinkle. And she has help. Each week in November and December, a box of Santa letters is sent over to the nearby Middle School where the town's 11- and 12-year-olds - the sixth graders - write back in the guise of elves. It is part of the curriculum.

But there's something else - something bad. Six of last year's Middle School elves, now aged 13, were arrested back in April for being in the final stages of plotting a mass murder, a Columbine-style school shooting. The information is sketchy, but apparently they had elaborate diagrams and codenames and lists of the kids they were going to kill. I've come to North Pole to investigate the plot. What turned those elves bad? Were they serious? Was the town just too Christmassy? I need to tread carefully. So far I've only tried to ask one person about it - James, the waiter in Pizza Hut - and it went down badly.

"North Pole is the greatest place I've ever been," James told me as he poured my coffee. "The people here are always ready to do! We stay on track and we move on forward! We don't let anything get us down. That's the spirit of North Pole and the spirit of Christmas."

"I heard about the thing with the kids plotting a Columbine-style massacre," I said.

At this, James let out a noise the likes of which I've never really heard before. It was a heart-wrenching "Aaaaaah". He sounded like a balloon being burst, with all the joy escaping from him like air. "That was a, uh, shock..." he said.

"You have to wonder why..." I said.

"This is a very happy, cheerful, cheery place," said James. "Anything more you need?"

"No," I said.

And James walked back to the counter, shooting me a sad look, as if to say, "What kind of a grinch are you to bring that up?"

Monday night People keep telling me that everybody in North Pole loves Christmas. But I've found someone who doesn't. In fact, she hates Christmas. Her name is Jessie Desmond. I found her via MySpace. "Christmas is a super big deal around here," she emailed me before I set off for Alaska, "but for me it is a general hate. Please don't go off me about that."

We meet in a non-Christmassy bar of Jessie's choice on the edge of town. She's in her early 20s. She was educated at Middle School, and is now trying to make her way as a comic-book artist. She has a Batman logo tattooed on her hand.

"Christmas really grates on me, all the time, in the back of my head," she says. "Christmas, Christmas, Christmas. It drives me nuts."

"But there must be something you do like about North Pole," I say. Jessie thinks about this. "Well, if you get into an accident or something, everyone's willing to help you," she eventually shrugs.

I decide it's safe to ask Jessie - being anti-Christmas - about the mass murder plot. "Do you know the boys?" I ask her.

She shakes her head.

"Apparently they drew up a list," I say.

"Well, I have a hate list on my wall, too," she says.

"Yes," I say, "but I'm sure you don't have access to weapons."

"I have a revolver in my bedroom," Jessie says.

"Do you stand in front of the mirror with it and shout 'freeze' and imagine what it's like to kill your enemies?" I ask.

There's a silence. "I might," says Jessie, finally.

I ask if she'll take me to her house and show me her gun. She agrees. Of course, Jessie has no intention of killing anyone, and on the way she tells me she suspects the boys were just like her - all talk - and the town only took them seriously because everyone is terrified of everything these days.

Although this is late October, Jessie's house is extremely Christmassy. Her parents, Mike and Edith (a former Miss Alaska), are enormous Christmas fans. "Did you see my Christmas balls up front?" Edith asks me. "The nicest thing about living in North Pole is you can leave your Christmas decorations up all year."

"Are there people in North Pole who don't like Christmas?" I ask.

"I don't know any," says Mike.

I glance at Jessie. She's sitting cross-legged on the floor at their feet, displaying no emotion.

Mike shows me the mounted head of a sheep he once shot. It's wearing tinsel.

"You never think that having decorations up all year round is too much Christmas?" I ask.

Edith shakes her head. "No," she says, firmly. "No, I love Christmas. It's my favourite time."

"Jessie," I say, "will you show me your gun?"

"Sure," she says.

I tell Mr and Mrs Desmond that it was lovely to meet them, and I walk with Jessie down the corridor. We pass a row of paintings depicting Santa in various festive settings, in front of log fires, etc. Across the corridor is Jessie's bedroom. It is free of anything Christmassy.

"Does your mother know...?" I begin.

"That I don't like Christmas?" says Jessie.

I nod.

"I've told her," she says, "but I don't think she believes me."

She rummages around her wardrobe and pulls out her revolver. "You're the first person to see it," she says.

She straightens her arm - a blank look on her face - like in a police movie. She says she sometimes pretends to kill the kids who bullied her in school. "I walk up to them when no one is around and I bop them over the head and shoot them!" she says. "Ha ha!"

Jessie says the person I should really ask about the plot is Jeff Jacobson. He teaches sixth grade at Middle School. He must have known the boys. Plus, until last week Jeff was mayor of North Pole. If anyone knows - and is willing to tell - it's Jeff, Jessie says.

And so I leave Jessie's house and I call Jeff Jacobson. He says I'm welcome to visit him tomorrow at Middle School during the lunch period.

Dusk is falling. One of the town's two giant Santa sculptures - the one outside the RV park - lights up. Eerily, however, it is lit from below, which gives Santa's eyes a hollow, creepy look, like Jack Nicholson in The Shining. I get an early night.

Tuesday morning Apparently the kids who were plotting the shootings were goths. Earl Dolman, the owner of the permanently Christmas decorated Dolman's Diner, the most popular restaurant in town, tells me this. Just about everyone who lives in North Pole eats breakfast at Dolman's. It has a lovely, festive, community feel, even if the decorations arestarting to look somewhat frayed and faded.

There's Twinkle the elf - Debbie - who looks as if she's been up all night opening letters to Santa and sobbing. "Being a letter-opening elf can do someone's head in," I think. There's Mary Christmas, who runs the Santa Claus House gift shop. That's her real name. It's on her birth certificate. And there's Earl Dolman. We get talking.

"Do you know anything about that shooting plot over at the Middle School?" I ask him.

"I know the kids were goths," he says.

"Really?" I say.

Earl gives me a look to say, "Well, of course they were goths. What else would they be?"

"Where I come from," I explain, "goths aren't dangerous."

"Really?" says Earl, surprised.

"Goths don't do anything bad in the UK," I say "They're a gentle and essentially middle-class subculture."

"Huh!" says Earl.

"I suppose the difference is that the goths in Britain aren't armed," I muse. "They're so death-obsessed, it's probably good to keep them away from guns."

Earl gives me a look, as if to say, "There's nothing wrong with gun ownership."

Then he tells me that - as a result of the shooting plot - his daughter has pulled her kids out of Middle School. The Dolman kids are being home-schooled now. "It shook everyone up," says Earl.

Earl says the goths were non-Christmassy outcast loners, bullied by the jocks, their intended victims. Iwas a bullied goth at school and so I understand the impulse to want to kill bullies. But there's a big difference between them and me. There were 15 of them. Six ringleaders and nine others who knew about it and were to play subsidiary roles. A gang of 15 can hardly call themselves bullied loners.Fifteen is a huge number in a town of 1,600. It's 25% of the school's 13-year-olds. And they were going to kill dozens of their classmates. This sounds to me like civil war, the non-Christmassy kids against the Christmassy ones.

I have an hour or two to kill before I'm due at Middle School to meet Jeff Jacobson, the plotters' maths teacher and former mayor. So I visit a sweet, twinkly-eyed lady called Jan Thacker, local columnist and author of 365 Days Of Christmas: The Story Of North Pole. Her book begins, "So does he? Does Santa really live in North Pole? ... The police chief believes it, and who is more honest than the chief of police?"

Jan and I chat for a while, and then she takes me into her back room, which is full of guns - a glinting rack of them - and a number of stuffed wolves that she's killed. The wolves have ferocious facial expressions. They're snarling, their eyes aflame with hatred, ready to pounce. I tell Jan she must have been very brave to shoot those terrifying wolves. "Were they really pouncing like that when you shot them?" I ask.

There's a silence. "No," she says. Then explains: the local taxidermist, Charlie Livingstone, tends to give the wolves ferocious expressions however they were behaving at the moment of their death - even if they were all doe-eyed, looking for a pat.

It's surprising to see someone so twinkly-eyed so heavily armed, but this is normal for North Pole. It solves the mystery of where the plotters would have got the guns. There are guns everywhere. This is mainly because of the bears. There are bears everywhere, and moose. I suspect this is why the town is so Republican. There are virtually no liberals. When you've got that many bears, you're not going to be liberal. You know what liberals are like with bears. We just scream. We let out a high-pitched scream and run away, our arms in the air.

It is all the more surprising, then, that Jeff Jacobson is a sweet-natured liberal, a card-carrying Democrat. I've been told that sometimes, at night, Jeff can be seen driving around quietly putting up decorations in underprivileged parts of town. Now it is lunch time, and he is putting up decorations in his classroom. He's wearing a Santa hat and a tie covered in snowmen. We talk a little about how much he misses being mayor.

I don't think Jeff gets on with the new mayor, Doug Isaacson, who's apparently a steely-eyed, shaven-headed Bush Republican. Isaacson's big idea is apparently to get all the shopkeepers in town to wear elf costumes as a means of generating increased tourist revenue. Jeff feels this is just window dressing and it's what's on the inside that counts, Christmas-wise.

Jeff tells me this is a good week to be in North Pole. Tomorrow his sixth graders - his 12-year-olds - will get their first ever batch of Santa letters to answer. They'll give themselves elf names and write back on Santa's behalf. "We live in a world of text messaging and video games," Jeff says. "Being a Santa's elf connects us with real people all around the world."

"Can I come along and watch them do it?" I ask.

"Of course," Jeff says.

"Jeff," I say, "I hear some of last year's elves were caught plotting a mass murder."

For a second Jeff freezes, Christmas decorations in hand. Then he recovers, and carries on pinning them up. "It was going to be on a Monday," he says.

"How was it thwarted?" I ask.

"One of the kids - the one who was going to be bringing the weapons in - didn't show up that day," Jeff says, "and so they postponed the plan. And while they were discussing the postponement, the plan was overheard, and the police intervened."

"And what was the plan?" I ask.

"They were going to bring some knives and guns in," he says, "and they were going to kill students and teachers. They were going to disrupt the tele phone system. They knew where the telephone controls were. And they were also going to disable the electricity. Turn off the lights. And carry out their plans. And these were well thought-out plans. They had diagrams. They had a list..."

"How many people were on the list?" I ask.

"Dozens," says Jeff. "And each kid was assigned who was going to do who. With what."

"Oh my God," I say.

Jeff shrugs. Then he smiles. "Saying all that," he says, "these boys had just turned 13 years old. They were going to disable the telephone system. That sounds terrifying, right? Well ..." Jeff rummages around in his pocket and pulls out his mobile phone. He gives me a look to say, "Well, duh!"

"So maybe they once saw someone in a James Bond movie disable a building's communications system," he says.

The more Jeff tells me about the plot, the more it strikes me as a mix of very chilling and very stupid. For instance, after the shootings, Jeff says, the boys were going to run to the station and catch a train to Anchorage, where they'd create new lives for themselves using aliases. One boy's alias was going to be John Wayne. The thing is, they hadn't checked the train timetables. The shootings were going to occur at lunch time in the cafeteria. Even if they gave themselves an hour to kill their enemies and get to the station, they would still have had a five-hour wait on the platform for the Anchorage train.

It was an ill-thought-out plan.

Lunch time is over, and Jeff's sixth graders run into class. Some gasp, thrilled, at the Christmas decorations. They are only 12, just a few months younger than the plotters, and they look like little children.

"To see those little boys in handcuffs ..." Jeff says. "I taught five of them. It broke my heart. As teachers we had to carry on like it was a normal day. But we were being ravaged inside with our emotions. Some teachers were having anxiety attacks. One is still suffering badly with stress ..."

I wonder if the whole thing was just kids' talk and they were never really planning to commit mass murder. Maybe it was just a fantasy to them, no more real than the Christmas fantasy is to the adults here, or the fantasy of the ferocious wolves is to Jan, the twinkly-eyed huntswoman. I'm not allowed by law to meet the kids, but I'm determined to meet at least one of their parents. I ask Jeff if he'll try to arrange this. He promises he will. I tell him I'll see him tomorrow afternoon for letter-opening elf class.

Wednesday morning Doug Isaacson, the new mayor of North Pole, stands atop a snowy nature trail and surveys his town below. "Imagine being in England 2,000 years ago, when your towns were just getting started," he says. "How would you set them up for future generations?" He pauses. There's a look of real passion in his eyes. "That's where we are!" he says. "We can do that here! That's awesome."

"How old is North Pole?" I ask.

"Fifty years old," says Doug.

"You're a founding father," I say.

"Very much so," says Doug.

This is Doug's first week in office. He says he was elected on a Christmas mandate. His campaign centred on the proposition that while North Pole is very Christmassy, there is room for it to be even more Christmassy.

Recently, Doug went on a fact-finding visit to the small Washington town of Leavenworth, where everything is Bavarian-themed. Many shopkeepers there wear lederhosen and sell bratwurst. As a result, Doug has had an idea. It is an idea he recognises will be a hard sell to the people of this wilderness, freedom-loving town. But the idea is this: Doug would like the shopkeepers of North Pole to wear elf costumes. He wants North Pole to be a fully-fledged theme town, with a Santa's Secret Village and lots of townspeople wandering around in costume.

"Many people move to Alaska because they don't want to be fenced in," I say. "So if you say, 'I'm going to fence you in with elf costumes...' Might that be an issue?"

"Absolutely," says Doug. "But let me show you something." We climb into his pick-up truck. He drives me around town. "Some people," he says, "think North Pole looks like a truck stop. And that's unconscionable."

We drive past Dolman's Diner, then past the utterly unfestive computer shop-cum-video game arcade, where I see teenagers playing violent shoot-'em-ups. Doug says he has half a mind to turn up unannounced at the not-Christmassy-enough businesses, introduce himself as the new mayor and ask the owners to start wearing elf costumes.

"We should do it!" I say, enthusiastically.

And so we do.

· Story continues here