"Steam Girl makes gadgets." She rummages around in her bag, finally holding up what looks like a rusty old Swiss Army knife. Screwdrivers and pliers and mangled bits of wire stick out in all directions. There's even a tiny wooden teaspoon.

"The Mark II Multifunctional Pocket Engineering Device," she announces triumphantly. "One of Steam Girl's first - and best - gadgets. Got them out of many a sc.r.a.pe, like the time they were captured by troglodytes on the moon and locked in an underground zoo. . . ."

She's talking pretty fast and waving her arms in the air, and I take a step back to avoid getting stabbed by that thing in her hand.

"Steam Girl used this to pick the lock on their cage, and they managed to get back to the Martian Rose just in time," she continues, half closing her eyes. "As they lifted into s.p.a.ce, the troglodytes in their tunnels howled so loud that the ground shivered and shook and the moondust rippled like windswept waves. . . ."

"Um . . ." I don't know what to say. "So you - uh - you made all this up, huh?"

She goes very quiet. Then she grabs the notebook out of my hands and shoves it into her bag.

"See ya," she says, and runs off before I can reply.

I've never been what you'd call a popular kid. I'm not very smart, I'm lousy at sports, and between the oversize teeth and the woolly black hair, I'm kind of goofy looking. My mom always says I have "hidden talents," but I gave up looking for them a long time ago. I'm used to being on my own.

I have had friends. In fact, once upon a time I used to hang out with Amanda Anderson, the prettiest girl in school. We live on the same street, and when I was six or seven, her mother used to visit my mom for coffee. Amanda and I would play together with LEGOs and dolls and stuff like that. My parents didn't approve of gender stereotypes, so sometimes they'd buy me girls' toys. I had a pretty cool dollhouse and some Barbie accessories that Amanda adored. It was all the same to me; I'd play with anything.

But one day at school, Amanda told everyone about my Barbie dolls. You can imagine the mocking I got after that. When I told my parents what happened, they called Amanda's mother on the phone and they never came for coffee again.

I'm glad my parents stood up for me, but I kind of wish they hadn't made a scene. I mean, it's not like Amanda and I were best friends or anything; we hardly said a word to each other at school. But she was really pretty, even back then, and I guess I hoped that one day, maybe. . . . Well, you get the idea.

What's really sad and pathetic is that I still have hopes, after all these years. You know, like in movies, when the hot popular girl suddenly falls totally in love with the unpopular nerd and dumps the arrogant macho football jock? Only, in the movies the unpopular nerd is played by a good-looking film star, while in real life he's played by me.

These days Amanda goes out with Michael Carmichael, who hit p.u.b.erty three years before I did and plays ba.s.s in a hardcore band, and who once put a lit cigarette down my trousers on the way home from school. It took nearly five minutes to get the d.a.m.n thing out, and I ended up with blisters in places you don't want to know about. I don't really get why Michael's such an a.s.shole. It's like he feels personally offended when someone is ugly or stupid or clever or different. Like it makes him really angry. I almost feel sorry for him, being like that. But then he pushes past me in the hallway with Amanda Anderson on his arm and I don't feel sorry anymore.

Anyway, as I was saying, I don't really have any friends. Most of the time that's OK. At home I play a lot of online games by myself. I know a lot of people treat those games as a big social thing, with loads of chatting and friending and all that. But not me. I just go on quests and kill monsters and level up and earn gold and stuff. That's what I like about it: even a loser like me can actually achieve something, just by pushing keys and putting in the hours. I wish real life were more like that.

Now and then, the loneliness is more than I can bear. So I try things like smiling at people in cla.s.s. Sometimes they smile back. And sometimes they look like they want to punch me or else throw up. And then I feel worse than ever. Once, I smiled at Amanda and she smiled back. Then after cla.s.s Michael pushed me up against the wall and told me to stop creeping out his girlfriend.

So when the new girl ambushed me at the gate, I didn't know what to think. Is she stalking me? I've never had a stalker before (obviously), but I sometimes wish I did. But in the fantasies, my stalker would be gorgeous, blonde, and crazy with l.u.s.t. Not just, y'know, crazy. . . .

Still, I have to admit, that notebook is pretty d.a.m.n cool. That night as I'm lying in bed, my mind keeps drifting back to the shivering moondust, the Martian Rose, and - of course - Steam Girl. Who, come to think of it, is gorgeous and blonde.

So in the morning, when I see that leather flying helmet bobbing along in a sluggish tide of hoodies and greasy hair, I find myself pushing through the crowd to catch up.

"Hey," I say as casually as I can.

She barely looks up. "Hey."

"How come I didn't see you before last week? Did you move here or something?"

Instead of answering, she takes hold of my arm and steers me out of the flow and into an empty alcove. I'm too surprised to speak.

"Listen," she says, still holding my arm. "Do you want to meet me at lunchtime?"

"Uh . . . sure. I guess." I'm not at all sure I want to, but what else can I say?

"By the incinerator. A quarter past twelve." She makes it sound like a mysterious secret rendezvous.

And then she lets go of my arm and disappears back into the crowd.

"Where Steam Girl comes from, even the laws of physics are different. There's a little magic in technology. Things are . . . less drab, less logical, less straightforward. Everything's a little more . . . possible."

We're sitting on a wall behind the incinerator block. The air smells of smoke and garbage, but there's no one else around, which is a big advantage. I'm flicking through her notebook, drinking in the drawings of Steam Girl's long legs and sly smile.

"Take the Martian Rose," she says. "It's the greatest airship ever made, with an amazing motor called the Spirodynamic Multidimensional Concentrated Steam Engine. I'm not sure exactly how it works - something about cycling steam through several dimensions at once to magnify its power. It was invented by Steam Girl's mother, who mysteriously disappeared when Steam Girl was still a baby. She was an inventor, too. . . ."

"What's this?" I say, holding up the notebook.

"Oh, that's Mars," she says. The picture shows a fairy-tale palace, perched on the side of a huge red mountain. In the foreground are several men in armor, each riding the back of a strange giant bird. "Skimmer birds," she explains. "They're not really birds; they're more like flying dinosaurs, but covered in shiny green-and-yellow scales that almost look like feathers. When the sun hits them, they shimmer and flash like a thousand colored lights. It's beautiful. . . ."

I glance up at her. She's slowly swinging her legs and staring into the distance at nothing. There's something very serious about the way she speaks.

The next drawing seems to be inside the palace. A tall, slim man with a long white beard, sitting on a throne.

"When we first arrived," she says, "we were taken to see King Minnimattock. The Martians were really nervous, because they'd never seen people from Earth before."

"Who's that?" I ask, pointing at a dark-haired young woman standing beside the king.

"Oh, that's Princess Lusanna, the king's daughter. As soon as she saw Steam Girl's father, Lusanna started blushing like the sunrise. Apparently, that's what Martian women do when they fall in love. . . ."

She glances at me for a moment, then looks down at her boots and continues talking.

"At first the king didn't know what to do with these strangers from another world. So he summoned the Royal Oracle, who turned up in a long black cloak, a dark hood covering her face. But when she entered the room, the oracle gave a strangled cry and fell to the floor in a faint. All the guards pointed their spears at Steam Girl and her father, and even the king drew his sword. Things looked pretty grim."

She slides off the wall and starts pacing up and down, stretching her arms over her head.

"That's when Princess Lusanna intervened, pleading with her father to give the visitors a chance. The king hesitated. The earthlings claimed to have come in peace. What's more, it was clear that his beloved daughter had taken a powerful liking to one of them at least. But the fate of his kingdom - maybe the entire planet - could be at stake!"

By now, I've forgotten about the notebook, the incinerator smell, the stale sandwiches and warm juice at my side. I'm completely caught by her words, the sound of her voice. I watch as she strides back and forth across the dirty asphalt, lost in her story.

"Then Steam Girl had an idea. She curtsied to the king"- as she says this, she drops into a clumsy curtsy herself -"and said she had a gift for him and his lovely daughter."

Her pacing has brought her to the side of her schoolbag. She crouches and draws out a small metal object, cupped in both hands: a tiny artificial bird, made of metal and wood, held together by miniature hinges and levers.

"Wow!" I say.

"The Clockwork Sparrow," she says. "Just a little trifle Steam Girl had made during the long journey from the moon to Mars. Now she held it up for the king to see, and she wound the spring-driven motor - like this. . . ."

I hold my breath as she turns a key no bigger than a baby's fingernail. There's the sound of small metallic teeth catching and grinding.

"And then she opened her hands and let go. . . ."

The Clockwork Sparrow drops like a stone, hitting the ground with a painful clatter. We both stare at it in silence. Then, just for a moment, it comes to life: rusting wings flutter, the tiny beak opens and closes, and the whole bird shuffles sideways along the asphalt. And then it lies still.

"Well, it worked better on Mars," she says, lifting the broken metal body and turning away.

"That was . . . awesome!" I say, jumping down from the wall. "Where did you get it? Can I see?"

But she's already put it away.

"Never mind," she says, pulling her bag over her shoulder. "The bell's about to ring."

"You can't stop there!" I say. "What happened with the king? And - what's her name? - Lucy?"

I follow her all the way to E Block, but she won't say another word. And sure enough, the bell rings just as we reach the door, and I have to go to gym cla.s.s.

After that, I'm hooked. We meet up most days for lunch by the incinerator. She tells me about Steam Girl while I look at the pictures in her book. Sometimes she turns up without any lunch, so I share mine. Soon I'm bringing twice as much, just in case, and an extra bottle of orange juice, which she really likes.

The stories get longer and more complicated: voyages of discovery all over Mars, with monsters and volcanoes and narrow escapes from angry native tribes. But throughout it all, their friendship with King Minnimattock and Princess Lusanna grows. Sometimes the old king and his daughter would come with them on the Martian Rose, delighted at the chance to explore their home planet. And, of course, Lusanna still glowed bright red whenever Steam Girl's father was around.

Not everyone on Mars liked the newcomers. The king's son, Prince Zenn.o.bal, seemed to resent their popularity, especially after Steam Girl rejected his amorous advances with a well-placed right hook. And the Royal Oracle hid in her laboratory when they were in town. But everyone else was having too much fun to notice.

And then there are the gadgets. The Motion-Powered Wrist-Mounted Monodirectional Lantern (a tiny metal box that faintly glows if you jump up and down for long enough), the Audioscopic Motion Capture Device (a tin cup full of wood chips and wax that supposedly records sound), the Portable Kitchen (actually a beat-up old gas cooker covered in rubber tubes), and my favorite: Steam Girl's Spring-Motivated Vertical Propulsion Boots. These last ones turn up in a story involving giant bloodsucking insects who live in a deep canyon called the Mariner's Valley. Steam Girl was trapped at the bottom of a pit, listening to the buzz of the thirsty insect swarm getting closer and closer. But then, at the last moment, she reached down to flick a tiny lever on her lace-up boots and . . .

"And what?" I say as she slips into one of her long, teasing pauses, gazing up at the sky. We're sitting as usual on the low concrete wall behind the incinerator. "Come on . . . !"

A lazy smile spreads across her face, and she slowly slips down from the wall. There are a couple of tiny metal clips on the soles of her boots. She spends a moment fiddling with these, then straightens up and grins.

"A little modification Steam Girl made to her boots back on the moon," she says. "Very useful on low-gravity planets like Mars. . . ."

She bends her knees and jumps. At first I think the soles of her boots have come right off - but then I realize they're still attached by thick round springs that stretch and bounce as she leaps into the air. I laugh pretty hard at that - and even harder when she lands flat on her b.u.m.

She glares at me, brushing off her skirt. "Like I said, they work better in low gravity."

We spend a half hour mucking around with the crazy spring boots. She even gets me to try them on, though they don't really fit, and I fall over straightaway. I sc.r.a.pe my knees and get a bruise on my chin, but I'm laughing too much to care. It's the first time I hear her laugh, and I like it. She kind of giggles - but not a high-pitched girly giggle, like Amanda and her friends. It sounds almost dirty.

Anyway, in the story, Steam Girl's boots got her out of the pit to safety. And in a way, I guess they've helped me escape from the dreariness of school - at least for an hour or so, while it's just me and her and the gadgets and notebook.

But then the bell rings and we have to go back to cla.s.s and real life. And let's face it: real life sucks.

It doesn't take long for people to notice I've made a new friend.

"How's your girlfriend?" they say.

"She's not my girlfriend," I reply, again and again. For all the good it does.

Michael Carmichael seems to find everything about her personally insulting. And apparently he blames me.

"You're disgusting," he says, shoving me into walls and chairs and shelves and desks. "Makes me sick."

Even Amanda makes gagging faces when she sees us together. And once, in the hallway after English, she grabs at Steam Girl's flying helmet and tries to pull it off. I don't see what happens next, but everyone hears Amanda screaming like a scalded cat.

I ask about it over lunch, but all I get is a chilly glare and silence.

"From the noise Amanda made, I thought you'd ripped her face off," I say.

She rolls her eyes. "I hardly touched her. She's worse than the Shrieking Vines of Venus."

"The shrieking what?"

And then she gives me a little smile and starts to talk, and before long I've totally forgotten about Amanda and Michael and everything else.

But the next day I don't see her in the morning, even though I get to school early and wait by the gate till the bell rings. She isn't in cla.s.s either. At lunchtime I check by the incinerator. There's no one there. So I give up and go sit in the library, where it's peaceful and private.

That's where I find her, sitting on the floor between two shelves, sniffing like a little girl.

"You OK?" I say.

She's covering the left side of her face with one hand. I kneel down beside her but don't know what to say. So instead I just sit there saying nothing while she sniffs and gulps and keeps hiding her face, till finally the bell rings and we get to our feet and go to our separate cla.s.ses without a word.

So anyway, here's what she tells me about the Shrieking Vines of Venus, the day before Michael Carmichael gave her a black eye: When Steam Girl and her father had been on Mars for a few months and had already ticked off most of the items on King Minnimattock's places-to-see list, someone had the bright idea of going to Venus. Actually, it was Prince Zenn.o.bal's idea, which should have tipped them off straightaway, but everyone was too excited to be suspicious. Steam Girl's father had always wanted to see what the mysterious green planet was like, and the king couldn't wait to travel to another world. The preparations were made at lightning speed, and within a week, the Martian Rose was on its way to Venus, with Steam Girl and her father and a handful of pa.s.sengers, including the king and the princess. Zenn.o.bal had pulled out at the last minute, much to Steam Girl's relief.

"Venus was beautiful!" she says, eyes shining. "Like the greenest, thickest, most luscious jungle you can imagine. The forest rose hundreds of feet into the thick warm air. And there were flowers everywhere: huge orange blossoms the size of a house, with pools of sweet nectar where you could swim and drink at the same time. Millions of birds and tiny playful monkeys, who chattered and giggled and danced through the trees. It was paradise. For six days they flew over that vast green ocean of leaves, landing now and then to explore under the canopy. All their worries fell away, and they felt more relaxed and happy than ever before. They strolled through endless orchards munching on all kinds of fruit, swam in fresh clean rivers, and lay in giant palm fronds, watching as sunset turned the whole sky red.

"Everything seemed peaceful. There were no giant monsters or angry natives or dangerous traps. The only slight annoyance was a particular kind of vine that gave off an earsplitting shriek whenever you came near it."

"Aha!" I say. "The Shrieking Vines of Venus!"

She grins. "Luckily they were covered with bright-pink blossoms that gave off a sickly sweet scent, so they were easy enough to avoid."

There are drawings, too, in her notebook. My favorite shows Steam Girl and the princess doubled over with laughter, pointing at a puzzled King Minnimattock. A bright-red monkey the size of a kitten has made a nest in the king's beard and is curled up, fast asleep. Behind them the jungle is a dense tumble of leaves and flowers and vines. Tiny bluebirds fly overhead.

Over the page is a very different scene: a view from the airship with the jungle spread out below. A dark column of smoke rises into the sky from somewhere near the horizon. It's a disturbing picture.

When I ask about it, she stops smiling and goes quiet. I've never seen her look like that.

"Sorry," she says at last. "I was . . ." She trails off. "You see, this is where it all went wrong. . . ."

"How do you mean?" I ask.

She shakes her head. "Never mind," she says. "I'll tell you tomorrow."

But the next day is when I found her crying in the library, and after that things begin to change.

Around this time, Mrs. Hendricks shifts the seats around so Amanda and Michael aren't sitting together. Instead, Michael ends up next to me, and Amanda gets to sit with Steam Girl. Maybe Mrs. Hendricks thinks I'll be a good influence on Michael, which shows just how much she knows.

Day after day, I stare at them. The two girls, I mean. Amanda wears tight tops that show a lot of skin. Her spine is one long, graceful curve, and when she leans back and yawns, it's like a slow-motion movie. She knows Michael is watching, so sometimes she puts on a show, with plenty of stretching and hair tossing and brief stolen glances. Of course I get to see it all, too.

Next to that, Steam Girl's flying helmet and jacket seem even sadder than usual. She hunches over her notebook, like a big, shy bear trying to hide. The only skin that shows through all the dark worn leather is an occasional glimpse of the back of her neck. It looks pale and cold.

Some nights when I lie in bed, I try to remember Amanda's latest performance - her soft slim arms, her narrow waist. . . . But after a while all I can think of is a tiny sliver of cool-white skin.

It's a whole week before she mentions Steam Girl again.

I get to the incinerator first that day. There's a fire going and thick white smoke keeps drifting into my eyes. Even the concrete seems to be sweating. When she finally shows up, I don't notice till she's right in front of me. It's like she's come out of the smoke, like she is smoke. For a moment nothing seems solid, nothing's real. Then she reaches out and puts a hand on my arm.

"Are you all right?" she says.