I look up at the two faces displayed on the huge screens that line the square. The evening news headlines have run, and this is the final announcement before the advertisements start up again. A murmur of excitement ripples through the crowd in front of us as two words flash up underneath the faces.

Wanted criminals.

Excitement. Not fear or alarm, but excitement. But then, these people are Insiders. They don’t understand fear. Not real fear. The kind that has you constantly looking over your shoulder and viewing each person who smiles at you with suspicion. The fear that causes you to hide from the world, to choose to starve rather than reveal your identity and to betray your own neighbour to the government.

But admittedly, the two faces staring out at us don’t really look like dangerous criminals. They look like what we are: teenagers.

Names flash up above the faces. Aleesha Ramos. Darwin Trey Goldsmith. Such an odd name, Darwin. Trey suits him better. On the screen, he looks happy and relaxed, wearing a light blue shirt that I guess was his old school uniform. Today, he wears a hat to cover the blond roots that are starting to show through the black hair dye and his blue eyes flick nervously to mine as if looking for protection from the words that track continuously across the bottom of the screen.

Wanted criminals.

I inspect my own face, wondering when they’d captured the image. Unlike Trey, there would be no official record of me on their database. Tight, fearful brown eyes stare down at me, framed by wisps of dark hair torn loose from my usual braid. I must have been having a bad day.

I pull my pink scarf up over my head, take Trey’s hand and lead him around the edge of the crowd. We keep our heads down, trying to look like a couple out for an afternoon stroll. I catch a flash of yellow on black ahead and turn sharply, almost dragging Trey down a narrow alleyway.

“Metz patrol.”

Trey doesn’t reply, but his fingers tremble in mine. We turn left at the end of the alleyway and left again further up the street to bring us back to our original route. We both memorised the directions, but Trey lets me lead. For an Insider, he doesn’t know much about the layout of the city inside the Wall.

“What was your friend called again?” I ask.

“Theo.”

“And you’re sure this is the right thing to do?”

He nods and glances down at me nervously. The small lump in his throat bobs up and down. “Yes, I thought we’d agreed on this. People need to know the truth. If they know what the government have done, why our city has ended up like this, then perhaps they’ll finally do something about it.”

But what will they do?

I know Trey’s right, but I can’t get rid of the nagging voice inside that’s telling me that this is a really bad idea.

I’m so lost in my thoughts that I don’t notice the rhythmic pounding ahead until Trey pulls me back against a wall. The chatter of voices around us dies and is replaced by a low murmur of fear. A woman steps back onto my foot and stammers an apology.

“S’okay,” I murmur, too quietly for her to catch my Outsider accent.

The press of people intensifies as the crowd parts to make way for the Metz patrol. Glancing up from under my scarf, I watch them as they round the corner onto our street. They tower above the crowd, taller and broader than even the tallest Insider, and are protected from head to toe in black armour that seems to absorb all light. The only splash of colour is two parallel yellow stripes on either side of their helmets. These are our protectors. Our law enforcers. Our judges.

My fingers twitch toward the knife that’s hidden in my secret pocket. I know it would be a waste of a knife to attack them, but I’d feel better with the blade in my hand. But I stop myself. If someone were to see it, they’d call me out, know I’m an Outsider. Insiders don’t carry weapons. They don’t need to.

The pounding footsteps get closer. They walk in perfect time as if they’re one being. And then, as the first of them draws level with us, they stop.

I stare resolutely at the floor. A bead of sweat trickles down the back of my neck. Surely, they can’t have spotted us in this crowd? My heart hammers in my ears and my fingers creep down again to tug at the handle of my throwing knife.

A heavy silence falls over the street. Everyone’s waiting. I risk a glance up, but all I see is the back of the man in front of me. I’m not even tall enough to peek over his shoulder. I take a step to the side, but Trey’s hand reaches out to grip mine. His palm is slick. He gives a tiny shake of his head.

Don’t do anything stupid, Aleesha.

A child whimpers. The kind of whimper that’s a precursor to a full-blown tantrum.

“Who is the guardian of this child?” The Metz officer’s voice is toneless and gravelly. There’s no way to tell if the person inside is male or female. If there is a person in there at all.

I stretch up on my toes and strain to see between the heads of the Insiders in front of me but it’s no use. All I can see are the helmets of the Metz officers.

The child begins to cry. The officer repeats his question but is again met with silence. I move sideways to a break in the crowd, feeling Trey’s eyes bore into me. The child’s cries reverberate in my skull. Adrenaline fizzles through my veins and I fight to control my breathing.

The only reason they would detain the child would be if he was illegal. Like me.

The child’s cries turn to a scream as the officer reaches down and lifts him into the air. He’s perhaps two years’ old and dressed in Insider clothes, which is odd. A thread of doubt weaves its way into my stomach. Perhaps he isn’t illegal after all.

Just then, there’s a cry of fear and the sound of running footsteps. A woman appears, her hair flying loose from the tight knot on the back of her head. She runs awkwardly like she’s wearing high heels and her face is a mask of terror.

She skids to a halt in front of the officer and reaches up her arms for the child. “Please, he’s mine. We must have got separated …” She looks pleadingly up at the impassive black mask towering above her. For a second, they stare at each other, then, slowly, the Metz officer lowers the boy to the ground. The woman picks the child up and tries to soothe his sobs as she backs away.

“Wait.”

The woman freezes and there’s a sharp intake of breath from the crowd.

“Your chips.”

The woman holds out her right arm and the officer runs a gloved hand down the trembling limb. He does the same with the child. There’s a slight pause and then he nods.

“Keep a closer eye on your son in future, ma’am.”

I let out my breath in a rush, a strange sense of disappointment flooding through me. So, he was just an Insider boy, after all. I could have risked everything, put myself up in front of the Metz, to save someone who didn’t need saving. A few weeks ago, the thought wouldn’t have even crossed my mind. But that was before Lily.

The Metz move off and the crowd thins around me.

“What do you think you were doing?” Trey sounds pissed.

“Nothing,” I mutter. “Let’s go.”

Trey’s friend lives down by the river, or at least what was once the river. To me, it’s always looked more like a sea. Or, in the summer months, a muddy swamp. You can’t really smell it at all Inside. Out in Area Four, it stinks, especially when the tide is out. But I guess in here, people don’t use the water as a toilet or a handy dumping ground for bodies.

We weave our way through an ancient part of the city that dates from the time before the Great Flood. The stone buildings are dwarfed by the glass towers behind. The streets are quiet, even though it’s a weekend, and it doesn’t take us long to reach our destination.

“This is it,” Trey says as we turn down a street lined with modern apartment blocks. They’re blindingly white and each has a neat balcony with pot plants or small trees. I never realized that there were so many different types of plants until I came Inside. Outside, everything dies.

We pause in front of one of the apartment blocks. “Are you sure you want to go in alone?”

Trey nods. “It’ll be fine. Best that they don’t see you, just in case.” He sounds as if he’s trying to convince himself as much as me. I reach out and squeeze his hand. His skin is cold and clammy.

“He’s your friend, right?”

“He was my friend.” Trey sighs and steps forwards, scanning the list of names by the apartment door.

How far he has fallen. A few weeks ago, he was an Insider boy, son of a government minister, being educated at a posh school outside London. Now, he’s an illegal citizen, forced to live outside the Wall. I wonder if he wakes up some days thinking it’s all a dream.

Trey tugs the cap down over his eyes and presses the comm link up to his friend’s apartment. A voice answers.

“Is Theo there?”

There’s a pause, then another voice comes on the line, too faint for me to hear. “Theo? It’s me, Darwin.” There’s a muttered conversation, then the door clicks open and Trey disappears into the building.

I wander down the street, keen to get away from whatever security cameras may be around. The road is a dead end, the apartment buildings sloping down to the river wall. It’s a low, brick wall. I wonder what they do when the waters rise, but as I get closer, I spot the retracted flood barriers on either side. The evening sun casts a warm glow over the rippled surface of the water. Sunset is getting later. Spring is on the way.

My mother took me to look out over the river once, on an evening like this. We’d sat on top of a low building looking out as the sun bathed the city red. I’d asked her who lived in the towers that jutted up out of the water. She said no one did. Not anymore.

I don’t remember what we did after that. My memories of that time are few and as every year passes, they seem to fade a little more into the blur that was my early childhood. But I think that wasn’t long before she left.

Before she was murdered.

The sound of footsteps cuts into my thoughts.

“Hey.” Trey rests his elbows on the wall and drops his head into his hands. “I’m glad that’s over.”

“What did Theo’s dad say?”

Mr Johnston owns one of the news networks in the city. An important man.

“He took copies of the documents. Said he’d think about it.” Trey lifts his head to stare out across the water. “It was strange though. He didn’t seem that surprised by the information. Almost like he already knew.”

“He knew?”

Trey shrugs. “I don’t know, maybe I’m wrong. We’ll have to wait and see. Theo was pretty riled up about it.” He smiles and pats the backpack on his shoulder. “And we’ve still got the originals.”

The originals are plastic films. We found them in some ancient cabinets in the basement of the government headquarters the first time we broke in. I haven’t read them — I can’t read that well — but Trey’s told me what they contain. They’re records of what happened after the Great Flood when London was one big city. Before they put up the Wall. Before there were Insiders or Outsiders.

“Let’s go. We’re more likely to be noticed if we’re out on the streets after dark.” Trey starts back up the street. I take one final look at the dying sun, then turn and follow him.

We walk in silence until we’re almost back at the Wall. It towers behind the apartment blocks and houses, a shimmering array of colour that lights up the dark sky. I yawn, feeling suddenly tired. Perhaps Abby will let me stay at her house tonight.

Trey turns down an alleyway. I follow, stumbling on a loose piece of paving. Recovering, I frown as I try to place where we are. “Isn’t this a dead end?”

Ahead of me, Trey rounds the corner, then takes a step back. “You’re right. Sorry, wrong road.”

He turns toward me and the colour drains from his face. His eyes lock onto something over my shoulder. Slowly, I turn around and draw a knife from my pocket. But I know at once that it’s no use. There are three of them and I only have two knives. Not that a third would make much difference. There’s no weakness in that black armour. I take a step backward and the Metz officers take a step forward.

We’re trapped.