The park is down the street, round the corner and across the road. It takes about five minutes to walk it during the day because that road's a main road. It's gone midnight now, though, and there's not a car in sight. I can just walk across the road and by the time I reach the park gate it's only been three minutes since I left the house. The gates are locked, of course, but someone has bent the railings nearby and I can squeeze through.

From opening to closing time the park is always abuzz. Early morning dog walkers show up as the gates are opened and groups of lurking teenagers always need to be herded out before they're closed. Right now, however, it is empty, and silent except for the sound of rain falling in the trees. I proceed to the kids' playground, which is at the centre of the park and surrounded by another set of railings to keep the dogs out. These I have to climb over, but there's this handy tree I've found which proves to be useful for doing just that.

During the day, the most popular ride in the kids' playground is the roundabout. Until I started coming at night, I'd never once seen it stop for more than a minute before another bunch of kids came along. I never liked those, back in my day, and neither did Sarah. The swings were always more our thing.

There are three sets of swings. The first are for toddlers. They have those seats with leg holes in them so that the little ones don't go flying into the bushes when they inevitably let go of the chains. The other two are for everyone else, and are on either side of the massive climbing frame. It's to one of these I go and take out the dishcloth I hid in my back pocket the night before. The seats are made of plastic so repel water. It's just a case of wiping away the rain and then they're dry enough to sit on.

The chains creak as they take the strain of my weight. I always worry that I'm going to break them but these swings have been here since before Sarah was born. They were built to last.

This is the moment I always feel most guilty, when I know I shouldn't be here doing this. But it passes quickly. Then I start to swing my legs. Were I any taller then I wouldn't be able to. My heels just miss scuffing the rubberised tarmac as it is. The chains creak as I start to rock back and forth. It sounds so much louder when I do it, but I guess that's only because I'm doing it so late at night.

When I was a kid I never liked to go too high. I always used to hate the kids who would swing so high it looked like they might go all the way over the bar and fall off. These days I don't even get excited until I'm looking straight down at the ground, just hanging in the air for that split second before hurtling back down again. By that time I've stopped caring about the creaking chains.

One night I spent over an hour swinging in the rain, but I've only been here ten minutes when a voice says: "Roger? Roger Ellis?"

This all started five weeks ago, the first Sunday after Sarah's twelfth birthday. She's just started secondary school and has made more lifelong friends in her first month at high school than I ever did in my seven years at mine. Sunday always used to be the day she spent with Dad. It often felt like I was a live-in divorcee - and still does - but this way Mandy could get us both out of her hair whilst she cleaned the house, did the washing, put her feet up. Ever since Sarah was seven I have been taking her to the park at the weekend. We used to feed stale bread to the ducks during summer and catch tadpoles during spring. During winter, if there was snow, we used to take the old sledge with us.

But now she has homework. She's supposed to do over an hour a night but I've never seen her spend that long on it and she knows it. When it inevitably mounts up at the weekend she whinges about it over Friday dinner and then Mandy knows it too. Sarah always plans to finish it on the Saturday but she never does. She always just manages to finish it in time for Sunday tea, by which time it is too late for us to do anything. Mandy doesn't care as long as neither of us is getting under her feet.

Every week one of us has to sign her school diary. She always used to go to Mandy for that, even when Mandy was busy and told her to see me. She'd rather wait until her mum wasn't busy than let me do it. One time she had no choice. Mandy was staying at her sister's and Sarah would get into trouble if she didn't get the diary signed. I saw that she'd only had two pieces of homework to do all week but I pretended that I hadn't noticed. I wondered what she'd been doing in her room all Sunday afternoon, and why it was so much more preferable to coming down the park with Dad.

"Well, this is embarrassing," the bloke confesses.

Embarrassing, because I am not Roger Ellis.

"They should put street lights in this place," he says, laughing nervously.

"Don't worry about it," I tell him. I'm the one who has just been caught playing on the swings in the middle of the night and a rainstorm, but he's the one looking decidedly awkward as he beats a shuffling retreat. He has a squat little dog with him, one of those docile breeds of hound that never seems to bark.

All of a sudden, the mood for swinging has left me and I'm just aware of being cold and wet. It's time to go home. I get as far as that tree growing against the railings before I stop and look back. This is no less a strange time and place to be walking a dog than it is to be playing on the swings. Of course, when I look back, he isn't walking the dog anymore. It's hiding from the rain beneath the park bench to which he's tied it - and he is busy riding the roundabout.

I've always known that what I do at night is wrong, but I've never really noticed how strange it is as well. I watch him as he runs beside the roundabout, waiting until it's about to escape him before jumping on, and all the while keeping a grim and serious expression on his face. The dog watches him from its shelter. It has one of those droopy, lidded faces that makes it look bored and miserable all the time. It's almost as if it's been here too many times before.

I can't help it. I go over. He doesn't stop right away, but when the roundabout slows once more he doesn't start running with it again. He hops off on the other side, buries his hands in his pockets and looks over at me sheepishly.

"Do you do this a lot?" I ask.

"Do I come here often?" he says. "Yeah."

"Specifically here? I mean, I've never seen you before."

"I've never seen you, either. Though I'm usually here later than this."

"Oh. I'm usually here earlier."

"That explains it, then."

I nod. He nods. Beneath the park bench, the dog sneezes.

"Do you only come for the swings?" he asks me.

"Excuse me?"

"If you don't mind me asking, that is."

"Oh. Well. Yeah. The rest isn't really my thing."

"Same with me and this thing, then."

"I see. How long have you been doing it?"

"Almost a year now. How about you?"

"Only a few weeks."

"Bored?"

"Tonight? No. Just cold."

"No, I meant generally."

"Oh. No. No, I don't think so."

He grins. I can barely see his face, but his whole posture changes. He climbs back onto the roundabout. "You're here for the long term, then," he says, then starts to kick off. "If you're gonna get on, get on now."

"I should probably be getting back," I tell him.

"We can go on the swings if you'd prefer."

"What do you mean?"

"You wanted to talk."

"Oh. No. I just wanted to ask."

"Really?"

"I thought I was the only person who did this."

He chuckles. "Does it make it easier," he asks, "finding out you're not?"

"I don't know," I reply, scratching an itch behind my ear that isn't really there. "Maybe." He's made me uncomfortable, but when the roundabout slows down again I'm still standing there.

"Want half of my Twix?" he asks.

"Excuse me?"

"It'll be dry beneath the climbing frame."

"What?"

He takes the roundabout for a final spin, then hops off before it stops. The dog leaps up expectantly and begins to wag its tail. As he unties its leash he looks up at me. "If you don't have it then he will," he warns.

I'm going home, I decide, but I don't tell him that. So a minute later I'm sitting on the rubberised tarmac beneath the colossal climbing frame eating one half of a double Twix bar and it is indeed dry, just as he'd promised. The dog's tied up again, which it doesn't look too happy about. He feeds it some of his Twix then it sits down behind us and starts slapping the back of my thigh with its tail.

"I lied," he admits suddenly.

"What about?" I ask with my mouth full.

"How long I've been coming here."

"Why? How long have you been coming?"

"Nineteen years." He snorts. "How fucked is that?"

"It's a long time," I admit uneasily, more at the thought of myself still sneaking off to the park when I'm sixty than of him having been coming just as long.

"Not always to this park, of course," he goes on. "Parks all over the country, wherever I've lived. And not every night, either. It's not a compulsion with me, you see, not like some of the guys who come here, the ones who only do it a few times. It's something I want to do. Something I like to do, even. How old is your son, by the way?"

I'm thrown. "Excuse me?"

"Daughter, then. Sorry, I thought you had a son."

"No," I say slowly. "I never said that."

"Oh, no, I know you didn't. I was just guessing."

"Well, what gave you that impression, anyway?"

He brings his knees up to his chest and wraps his arms around his legs. The answer he gives me is a considered one. "Just a pattern I've noticed," he explains. "After a couple of decades you begin to see what the people who come here have in common. I have a little theory about it. Fathers who have sons who grow out of going to the park with daddy, and daddy realises if he doesn't go on his own then he'll never go again. I don't know what it is about parks. Maybe that's just some people. Maybe there are just as many hanging around toy shops. Maybe buying toys. Maybe even playing with them."

I laugh. "That's not me."

"It's not me, either, but still..."

The dog stands up, walks as far as its leash will allow and then sprays the side of the climbing frame. There's a reason that dogs aren't allowed in here. It shakes a few drops of rain off its flank and then comes back and nestles between us.

"What about you, then?" I say.

"What about me?" he says, stroking the dog's head.

"Any kids? Or is it just you and Rover?"

"Yes, just me and Rover. His name's Mollusc. As in the shell fish."

I stroke Mollusc's head as well. "That kind of disproves your theory, though, doesn't it?" I put to him.

"I suppose," he says distantly. He's picking away at the rubberised tarmac between his legs, uncovering the earth beneath. He digs out a little hole and when it's big enough to stick his finger in, he screws up the Twix wrapper and buries it. Then he pulls himself up with help from the climbing frame and unties Mollusc.

"Where are you going?" I ask.

"I'm think I'm gonna have a go on the swings, after all," he says. "See if I am missing anything."

Mollusc bounds ahead of him as far as the leash will let it. It thinks we're returning to the roundabout. It doesn't like being tied to the swings. There's nowhere for it to shelter from the rain. Its owner shakes the rain off the seat and then starts to swing. He really hasn't done this for decades. He's not even swinging his legs. But it comes back to him slowly, then he looks up at me.

"You should have a go on the roundabout," he tells me.

"I don't think I'm missing much there," I say.

"You'll never know," he warns. "One day you'll wonder, though, but by then you'll be too old to do it anymore."

"I think I'll risk it, all the same."

"You'll regret it. You will." He's building up momentum now, swinging just as high as I had been when he first appeared. And he looks like he's enjoying it, too; even Mollusc has picked up on that. The dog's standing up, wagging its tail. The peculiar thing is, I do feel like I'm missing out. Not on the swings, or the roundabout, but on something. Something I can't pin down yet.

The rain has started to ease off. Or perhaps I'm just soaked to the skin anyway and can't feel it anymore.

"You look pretty uncomfortable just standing there," he notices. "Why don't you join me, if that's what you really want?" And I would, if I thought it would feel any less awkward.

Just then, a middle aged naked guy runs through the middle of the playground, streaming with water that isn't rain, stops only to make a "Moo!" sound at us, then runs on his way. Mollusc decides it's time to take up barking.

"Can you imagine what kind of crazy world we'd live in if people were just themselves all of the time?" Mollusc's owner says quietly.

I laugh. Then I have my own confession to make. "Twelve," I say.

"I beg your pardon?"

"My daughter. That's how old she is."

"Oh," he says. He stops swinging his legs. He slows down fast. Then, quite spontaneously, he asks, "When was the last time you climbed a tree?"

I look round. The naked guy has just passed my ladder tree and I don't want it to look like I'm pointing at him. "I have to climb over that to get in here," I say.

"I meant a proper tree," he says. "Not like that overgrown bush. A proper tree's like that conker tree over there."

A single horse chestnut tree grows within the fence to the kids' playground. It's taller than a house and has probably been here longer than the park itself. If that is a proper tree, then I have never climbed one.

"It's been some time." I grin.

"Come on, then," he says, hopping off the swing.

"I don't know," I say.

He ignores me and unties Mollusc. Wrapping one end of the leash around his fist he heads for the tree and I follow like another puppy. The tree looks even taller from the bottom of it. I never knew how to climb these when I was a kid so always used to get left down here waiting for the others to grow bored. The good thing about my overgrown bush was that every branch was another notch on the ladder. The bad thing about his proper tree is that every branch is several feet apart.

"You first," he says. He's looking for something at the base of the tree.

"I haven't done this in so long," I tell him.

"I have to tie Mollusc up. Go on." He's looking for a stick. He finds one as I start to climb and drives it into the earth. Then he wraps Mollusc's leash around it and Mollusc begins to whimper.

I start to climb but am at loss before I've got more than a few inches off the ground. When I look back for help, though, he's sitting at the bottom of the tree with Mollusc between his legs and an action figure in each hand.

"He likes playing with these," he tells me.

Mollusc has indeed stopped whimpering, though it only looks interested in the toys because its owner is waving them in its face. He sticks their plastic feet into the wet soil beside the stick and leaves Mollusc to sniff them.

"Come on, then," he says, dusting his hands together. "Let's climb up."

I climb back down. "You go first," I tell him. "I really don't know how."

I stand back beside Mollusc, the stick and the toys as he begins to shimmy up the tree trunk. He does this until he can reach the first branch, then he pulls himself up to a knot in the tree, which he spurs the side of his foot into.

"Easy," he breathes.

I get the impression he's climbed this tree before.

"Come on, then."

I begin to climb, shimmying, pulling and spurring just as he did.

"That's it," he says.

So soon I am as far into the tree as I can climb and I'm exhausted and my heart is beating fast and this is, for some stupid, crazy reason, really quite exhilarating. "Shit, I think I've got my foot stuck," I mumble.

He stops trying to climb any further and glares down at me. "That is so unfair," he says quite abruptly.

"Yeah, well, I've never done this before, have I?"

"No, but I've been doing this for decades and I've never got my foot stuck."

"You're not missing out on anything, seriously."

"Yeah, but how do I know that?"

"Because I'm telling you."

"I want to get my foot stuck," he decides. And he's serious. When I look up he's sticking his foot in every knothole and crevice this twisted tree has to offer and very quickly I'm in hysterics. Not because it's funny but because it's so crazy and stupid and he's so fucking serious about it.

"Really, don't," I say. "If you get stuck, who's gonna get help?"

He stops struggling, looks down again, and grins. "Too late," he says.

"Oh. Great."

We're still in the tree at dawn. In a couple of hours the gates will open and we'll be discovered by the dog-walkers. Part of me doesn't care in the slightest, but part of me cares what Mandy and Sarah will think. It's pretty uncomfortable up here, but I've been stuck in the same position for so long I can barely even feel my trapped leg anymore. We don't talk much, though not because there's nothing left to say.

"You know what, I wish I'd learnt to play guitar," I tell him.

"I learnt guitar," he mutters. "Wish I'd joined a band, though."

"I sung for a band once."

"Really? Who were they?"

"Just some kids back in high school."

"Did they ever get famous?"

"They could have done. I only went so they'd share a joint with me."

"I've never smoked pot."

"You didn't miss much."

"I'm starting to wonder now."

"The funny thing was, I couldn't even sing."

"Oh, I used to be in a choir. A few years ago now."

Our conversation continues like this, back and forth, for several hours. By opening time I've got the impression that the only thing we have in common is that we're now both stuck in this tree. He waves and says hello to the first person that walks by on the other side of the railings with a dog. They're startled, glare up at us in the tree, then go on their way.

"I'll give him five years before he's on this side of the fence," Mollusc's owner tells me. The poor dog is curled up asleep at the bottom of the tree, his action figures still stuck in the dirt beside him.

The police appear about twenty minutes later and speak to us like we're children. They tell us to climb down, we tell them we can't. My friend above me also challenges them to climb up after us and then they get really patronising.

"Come on, you two, you know you'll regret this when you're sober."

"We're not drunk!" I shout down.

"Yeah, and I only regret the things I don't do," my friend adds.

"If you don't come down now, we'll have to charge you for causing a public affray and resisting arrest, do you hear me?"

"We're stuck," I cry. "Honestly!"

But when I look up, he's evidently not stuck. He's climbing down, awkwardly. I can see why. He has a fist full of peeled horse chestnuts in his other hand, and now he has a crooked smirk on his face as well. "You ever been arrested for assaulting a police officer before?" he whispers to me.

"I've never been arrested!" I hiss.

He grins, chuckles. "Me neither."

Then he hands me some conkers and I get the idea.

NOTES:
This story invariably suffered for the second half being written a month after the first half. The only copy of this story was on my laptop when it broke down and in the time it was away I went off and wrote two other stories. The idea of writing about people expressing mid-life crisis by sneaking off to the park late at night came to me some time ago, but it was seeing "American Beauty" that finally motivated me to sit down and think it through. I found it hard to write, often only managing 100 words at a sitting, and I eventually came to the conclusion that this was due to it being a departure from what I usually write. This story revolves around basic human interaction far more than most of my stuff does. It relies on the characters rather than a plot to carry it through. Whilst these two men are middle aged, I think the kind of identity crisis they're going through can happen at any time. Though it wasn't a conscious decision, I suspect the character of Roger Ellis (who doesn't actually appear in the story) was named in honour of Bret Easton Ellis.