On his way to school, David kept a wary eye out for the van with tinted windows. He didn’t see it, but at the same time, he couldn’t shake off the feeling that he was being watched. He cycled slowly, allowing Philippa to keep up. He’d been worried that she would want to talk about Eddie again, but instead she just gave him knowing looks whenever she caught his eye. He was relieved when they separated at the bike sheds and Philippa ran off to her friends. She was lucky, David thought, as he walked into the building alone.

His first class was physics, which was almost enough to bring back the headache. The teacher droned at the front of the class and pointed to a diagram of something to do with space and time, while David struggled to keep his eyes open.

“Didn’t get enough sleep?” said a low voice behind him. David ignored it.

“Dreaming up some new stories about your dad?” said someone else.

David tensed.

“What was he last time?” whispered the first voice again. “Soldier, wasn’t it? Or astronaut?”

All around people snickered.

David wasn’t popular at school. He could never work out why. Perhaps he should have made more effort at the beginning, but it was probably too late now. And maybe it was his own fault for talking too much about a dad no one at school had ever actually seen, not even the teachers. It hadn’t taken some of the pushier kids long to decide he was just dreaming it all up. Either that or hiding the fact that his dad was in prison or something.

There had been real sympathy, though, when news spread that David’s soldier dad had been killed on some far-off battlefield. The head teacher had talked about it in front of the whole school, and even the kids who thought David was a joke looked at him with awe for a few weeks. But then someone noticed that he never talked about his father anymore — that he hardly talked at all, in fact. Suspicion returned, and it wasn’t long before everything was back as it had been before. Unable to explain how empty his life had become, David found another way to express himself. There were fights, and because David was stronger than he looked, he often won, triggering the perverse logic of all teachers that the winner of a playground scrap is always to blame.

“Astronaut?” hissed someone else. “Nah, you’ve got to be real to be an astronaut.”

David struggled to control his rage. He closed his eyes and tried to concentrate on the teacher’s voice.

“David Utherwise! David!”

David jerked his head up and blinked in surprise. The whole class had turned to look at him. One of the school secretaries was standing in the doorway, clearly annoyed.

“David, could you please report to Mrs. Fernley’s office,” she said, in a way that suggested she’d already said it several times.

The class started jeering, though they did that with everyone when they were called out. But the kids sitting behind him made here-we-go-again noises until the teacher started shouting at them.

David made his way to the door. He couldn’t think of any reason why the headmistress would want to see him.

“Have I done something wrong?” he asked the secretary as they walked down the corridor.

“Not this time,” she said, raising an eyebrow at him. “There are some people here to pick you up, that’s all.”

“Pick me up? But … where am I going?”

“Well, surely you know,” said the secretary.

David stared at the woman. There was nothing planned that he knew about, and his mum hadn’t left him one of her notes, he was sure of that.

“What kind of car did they come in?”

“They haven’t come in a car,” said the secretary. “It’s an ambulance.”

“Not a van, then?” said David after a moment, but the secretary ignored him.

They arrived at the office and David was shown in. Mrs. Fernley was sitting at her desk, and as soon as David saw her gray face, he knew that something was very wrong. For some reason the blinds were closed, leaving the room in semidarkness.

“David, there you are,” said the headmistress, her voice shaky. “Your doctor has come in person. Why didn’t you go to your hospital appointment today?”

David wanted to say, Because I didn’t have one to go to, but instead he looked at the woman who was sitting opposite Mrs. Fernley. Her face made David think of sharks, and her simple, chic suit had an unfriendly hint of uniform about it. Then he noticed there was someone else in the room. Standing in the shadows of the darkest corner was a teenage girl. She had white-blonde hair, and from her outfit she appeared to be a nurse, though in the gloom it was hard to be sure. The hairs stiffened on the back of David’s neck — it was hard to be sure there was anyone there at all.

“Now, David,” said the shark-faced woman, “if you’re ready, we’ll be going. We’ve taken an ambulance off normal duties to collect you.”

David blinked at her. Then he looked at Mrs. Fernley. “Old Sternley” ruled the school by force of presence alone — she was the kind of principal who could quiet an unruly class simply by entering the room. Yet here she was sitting meekly behind her desk, fiddling with her pen, her head bowed. David was shocked.

“I’ve just been on the phone with your mother, David,” Mrs. Fernley said eventually, her eyes never leaving the girl in the shadows. “She’s waiting for you at the hospital.”

“You’ve spoken to my mum?” said David in surprise.

Mrs. Fernley gave a startled nod.

“Yes, so let’s not waste any more time, shall we?” said the shark-faced doctor with a sickly smile, and her chair scraped the floor as she stood.

“But I don’t have an appointment at the hospital.” David stepped back. “Mrs. Fernley, I’m not even ill.”

At this, Mrs. Fernley seemed taken by a sudden doubt. She knitted her brow at David as if seeing him for the first time, and for a moment her normal expression of imperious authority returned — something David had never thought he’d be happy to see. She turned back to the doctor as if she was going to question her, but before she could speak, the nurse in the shadows stepped forward. She moved so smoothly it was almost as if she wasn’t touching the floor, and she looked at the teacher with furious intensity, her eyes as bright as pins. Mrs. Fernley drew in a sharp breath.

“Everything is fine,” the nurse said in a voice like frozen honey. “We are here to take David, that’s all. Everything is fine.”

Her voice was so persuasive that even David felt everything would be okay if he just went with them, no questions asked. As if sensing this, the doctor put her hand on his shoulder.

It was only as David found himself being propelled to the door that his alarm returned.

“But, Mrs. Fernley,” he blurted out, “I don’t know who these people are!”

Mrs. Fernley didn’t even look his way as she stammered out a reply.

“Try not to forget your hospital appointments in the future, David. Your health is important.”

Then David was out in the corridor, being swept along. The woman gripped him under the arm, so far up that he found it impossible to turn and confront her. And perhaps he really did have an appointment today — it wouldn’t be the first time he’d got something like that wrong. He managed to take his phone from his pocket and began to key in a number.

“What are you doing?” snapped the doctor. Then, in a softer tone, she added, “We don’t have much time, David. You can call your friends later.”

“I’m ringing home,” said David. No way was he leaving school with this woman without hearing from Mum first.

The woman didn’t reply, but marched him through the main doors and out to the parking lot, where an ambulance waited. David stopped, planting his feet firmly as he waited for an answer. The doors of the ambulance opened, and a young male paramedic, who could hardly be older than the nurse, leaned out.

At last, his mum picked up the phone.

“Oh, hi, David,” she said. “How’s school?”

“Mum, do I have an appointment at the hospital today?” David asked, one eye on the paramedic. David saw him smirk as he pressed a button on a console.

There was no reply.

The line was dead.

“It must be interference from the ambulance,” said the doctor. “Get in.”

But David didn’t move. The paramedic stared straight back at him with bright cold eyes, and David found he couldn’t look away. He’d seen that devilish smile before. It was the boy he’d seen on the roof of Eddie’s house.

He was staring at the strange boy from his dream!

The boy laughed at the look on David’s face, and then in a rush of movement he lunged at him, snatching up a syringe with his other hand.

David reacted instinctively. Before he knew what was happening, he’d used his foot to thrust himself back from the ambulance, knocking the doctor to the ground behind him. The paramedic’s grasping fingers missed by a whisker.

“Grab him!”

David leaped up, leaving the doctor winded on the ground, and ran for the school perimeter. He could already hear someone running behind him as he grabbed the bricks and hauled himself easily over the top. He dropped lightly to his feet on the other side and sprinted down the path, ducking quickly into a narrow passage between two houses. He wedged himself behind the trash cans and tried not to move, though his heart was pounding. After just a moment’s silence, there was a blur of movement at the end of the passage, and the nurse flashed past, moving faster than he’d have thought possible. He drew his head back, not daring to breathe. It was a full minute before he peered out again.

No one.

David released the air from his straining lungs, but almost immediately he caught movement in the corner of his eye.

Someone was down in the shadows at the other end of the passage, a slim silhouette. She had tangled hair, though the rest of her features were lost in shadow. She was beckoning to him.

“This way, David!”

David kept still and low. Who was she? How did she know his name?

The girl crept forward a little.

“Quickly! If you stay there they’ll find you.”

“Who … who are you?” David called, as loudly as he dared. But the girl didn’t reply. She simply beckoned to him again, then shot back down the passage. In a second she’d disappeared out the other side.

Whoever this new girl was, she wasn’t the freaky blonde nurse, and right then that was enough for David. He ran down the passage to try and catch another glimpse of her.

Stepping out into the street, David paused on the pavement. There was no one there, not even anywhere to hide. The girl had vanished so completely that once again he found himself questioning what he’d actually seen. Then, far, far down the road, the same tangle-haired head popped out from behind the trunk of a large tree and beckoned to him again.

David stared. How could she have got that far in just a few seconds? But he didn’t know what else to do, so he sprinted toward her.

David didn’t see the van until it had almost knocked him down. It screeched out of a side road and pulled up inches from his nose. The door slid open, and two pairs of black-gloved hands reached out and seized him. He opened his mouth to shout but a piece of damp cloth was clamped over his face. The cloth was soaked in something that filled his nostrils and instantly clouded his mind. He saw dark shapes. He focused briefly on the face of a man in a black visor.

Then the world went out like a light.