Ewan walked inside. The Experiment Chamber was far from what he had expected. He found himself in a small, caravan-sized control room lined with computers, swivel-chairs, microphones and telephones, bordered by a wall of glass that separated him from the main body of the chamber. Small adhesive signs had been stuck to the corners of every glass panel, reading ‘DANGER: no metal or metallic products inside the chamber’. Beyond the glass, the chamber contained very little – just a large pile of metallic objects in one corner that included weights, empty weapons and clothing with metal attachments. Meanwhile its tiled floor had been half-cleaned of powdery bloodstains: clone blood that had come to rest between two stone pillars.

Ewan checked the porthole-shaped window on the door. No sign of Alex approaching. He hoped his teammate was OK, wherever he was. Or at least alive.

‘Alex,’ he whispered into his radio, ‘updates?’

Silence.

‘Alex.’

‘Still far away,’ came Alex’s voice, tired and gasping. ‘Got chased the wrong way down the corridor by a load of biorifles.’

‘OK,’ answered Ewan. ‘I’m here now, so no worries. Head to the nearest stairwell and get as close to Floor B as you can. I’ll meet you up there.’

‘Got it.’

The radio went silent. Ewan was on his own, but the work could easily be done alone. And it started with making sure he was in the right place.

He looked back at the desk, trying to guess the uses of the several dozen buttons and levers across the control panel. The red button next to the microphone was obvious, and the palm-sized button on the wall labelled ‘kill switch’ must have been there to stop experiments before someone important got killed. The dial at the far right seemed to control the lighting for some reason, and for all he knew the brown lever delivered fresh coffee or something.

There was another red button, protected beneath a translucent panel of plastic so nobody would use it by accident. Ewan’s instincts, fuelled by a whole childhood of toying with anything that looked interesting, commanded him to push it.

When he did, there was a brightly-coloured burst of light on the other side of the glass, like a red camera flash. Ewan looked up, and lost his breath.

Between the stone pillars, he saw the same type of shield his team had watched light up the skies around Harpenden. The same type of shield that had surrounded Oakenfold, and killed Raj. He stared in hatred at the crimson waves that flowed between the pillars like vertical water, and the little lightning bolts that leapt out from the metal ‘border points’ – or whatever Raj had called them before he killed himself. After a brief squall of excitement, the shield faded into invisibility.