It was good to get out of the house. I did that big breathe-in-through-your-nose thing and exhaled with a loud “Haaah!”

Our house is on the very edge of the old bit of the estate. There are about ten tiny houses in a row, and then the new houses start next door. Over our back fence is just woodland. The woods don’t even have a name, so far as I know. They’re just “the woods” or “that bit of woodland beyond the golf course.”

It would be really cool if there was a gate in the back fence that I could just open and be in the woods, but there isn’t, so it’s just this wooden wall, basically, at the end of the empty, rectangular yard.

On one side is an alleyway piled up with junk and smelling of cats’ pee. There’s an old mattress, and a rusty washing machine, and a trash bag spilling out old clothes. Dad says it’s the council’s job to clear it up, but they’re obviously not interested. On the other side of Junk Alley live two ladies with short gray hair, Sue and Pru, who Mum has already met and declared “very nice,” adding, “One of them is a doctor.” (I always thought doctors were quite well paid, so I don’t know why they’re living round here.)

Their yard has been turned into a neat, paved garden, and they have about five rescue cats. (Dad snorted when Mum told us. “Never trust anyone with more than two cats,” he said, which I thought was a bit mean. I kind of like cats.)

On the other side of us is another garden, a real one with grass, separated from our yard by a rickety fence.

So on the morning it all started I was standing there with my back to the fence, staring at the old houses made of dirty bricks. Half of the houses look as though they’re not even occupied, and a couple have got broken windows. No wonder our house is cheap to rent. Mum and Dad say it’s only temporary.

“Hello, Aidan!”

I looked round, startled, but I couldn’t see anyone. Then the voice laughed: a short bark of high-pitched glee. A girl. I did a full 360, trying to figure out where it was coming from.

“Over here!”

“Where?” I said. And then, “Ow!” as something hard hit me on the cheek. A few seconds later, something whizzed past my nose.

“Hey! Stop that,” I said, and the terrier-bark laugh started again. Then I saw it: the yellow tube of a ballpoint pen withdrawing through a large hole in the back fence. Someone was using it as a peashooter to fire paper pellets at me, and she was a good shot.

I went over to the knothole and stooped to peer through it, and almost immediately felt a hard kick on my backside. Spinning round, I saw the tiniest girl grinning wickedly and cackling. I recognized her from school, although I didn’t know her name. We didn’t share any classes.

“Wh-where did you come from?” It really was as though she’d materialized from nowhere before my eyes.

“I’m Roxy Minto. I live next door. You’re Aidan!”

“Erm…I know. How did you know my name?”

She gave a little snort to show that she thought it was a stupid question. “How do you think? Your mum spoke to my mum. I saw your movers carrying stuff in. You’ve got a red bicycle and a white wooden desk in your bedroom. Turn around.”

“Why?”

“Just turn around.” She said it with such confidence that I found myself obeying, even though I half expected another kick in the pants.

“How do you know the bike and desk are mine?” I said over my shoulder, but there was no reply. I turned back…and Roxy had gone. Vanished.

“Roxy?” Then a plank in the fence that separates our gardens swung up, hinged on a horizontal strut. She poked her head through, giggling. “This way!”

It was a squeeze but I made it. (Roxy’s so tiny that she passed through and barely touched the sides.) And there I was in her overgrown garden, with ratty shrubs and flowers and weeds, and an old plastic slide.

Roxy strode through the uncut lawn to a massive bush that spilled over the fence and ran tendrils up a hazel tree. She pushed a branch aside and disappeared into it. Seconds later, I heard her voice on the other side of the back fence.

“Are you coming or are you too scared?”

I pushed aside the branch. The big bush concealed a hole in the fence that led to a path separating the back fences from the woods. Up against the fence, and completely hidden from the garden side by the bush, was a shed: one of the pre-made ones that you see on building sites.

Roxy stood in the doorway. “Welcome to my garage!” she declared in her squeaky voice, and I could tell she was proud. She reached inside for a switch and a neon sign hanging from the roof flickered to life. It said GARAGE in pink letters, but the first three didn’t work, so it just said AGE, but—I have to admit—it was still pretty good.

Inside was a battered desk, a wonky swivel chair, two wooden stools, and a tiny fridge in the shape of a beer can. There was carpet on the floor, a lampshade on the light, and even curtains at the windows. A very battered old sofa had yellow foam escaping from tears in the vinyl cushions. I laughed.

“What’s so funny? Don’t you like it?”

Secretly I thought it was completely awesome, but I wasn’t going to say that, was I?

“It’s OK,” I said. “Wh-where did you get all this stuff?”

I could tell she was disappointed with my reaction, and I immediately felt a bit bad. “Dumpster diving, mainly,” she said. “People chuck so much away in them, so, you know—reuse, recycle, blah-di-blah. The neon sign’s the pièce de résistance!” She did an exaggerated French accent and waved her hand theatrically.

“You’d never know there was so much in here!” I said, to make up for my earlier comment.

“Not much to look at, but plenty on the inside, you mean? That’s what they say about me!” She hopped onto a stool and reached across to open the fridge. “Fancy a beer?”

“I…er…”

“Kidding. Hey, you know ‘gullible’ isn’t in the dictionary?” And she tossed me a box of juice with a straw. “Have a seat. Take the weight off your feet. Mi casa es su casa!”

We sat for a bit, sipping our juices. I had known Roxy for about six minutes, and already I was certain that I hadn’t met anyone quite like her before.

When I said she was tiny, I wasn’t exaggerating. She was so small that, if I were guessing her age, I’d say about six, but her behavior suggested someone much older, more like sixteen. Her skin was a rich brown, with dark freckles across her nose, and her Afro was cut roughly and short. Her clothes gave nothing away: shorts, flip-flops, dirty white T-shirt, denim jacket. Standard kid-in-summer gear. Only, she had to be at least eleven because she was at Percy Academy.

It was her grin that I noticed the most, though. You know how some people, when their faces are resting, look naturally grumpy? It’s not like they’re in a bad mood or anything—it’s just that, when they have nothing particular to smile about, they don’t? Dad’s face is like that. People are always saying to him, “Cheer up, mate—it might never happen!”

Anyway, so far as I could tell, Roxy was the exact opposite. Her mouth seemed to be fixed in a permanent smile, as if she was laughing to herself about some private joke.

She caught me looking. “What you starin’ at? Haven’t you never seen a toff?” Suddenly her accent was that of a Londoner, and my surprise must have shown on my face. She laughed. “It’s a line from Oliver!”

I must have looked blank.

“Oliver! You know—the musical? Oliver Twist by Charles Dickens. When Oliver meets the Artful Dodger, that’s what Dodger says. We’re doing it in my drama club. I’m gonna be Dodger. I’ve got the costume and everything!” She pointed to a long velvet coat and a man’s hat on a peg.

That I could believe. “How old are you, Roxy?”

Her voice changed again, this time to a posh old lady’s: “How dare you ask a lady her age, young man!” She was clearly quite the actress, this new neighbor of mine. “Same as you. Four weeks older, actually.”

“You know my birthday?”

She jumped down from the stool and opened the shed door.

“There’s a lot I know about you, Aidan Henry Linklater. And your sister, Liberty, born on February the fifth. Put the juice box in the recycling there and follow me. There’s something I need to show you.”

I followed her into the woods, down a barely visible path. If only I had known what was to happen, I might have avoided a whole lot of trouble.

But I also would never have met Alfie Monk.