There was a yellow square taped to the steel floor. Butler stepped on it, raising his arms. Kurt performed a body search that would have shamed a customs official, before ushering him through a metal-detector arch.

‘He’s clean,’ he said aloud. The words would be picked up by the microphone on his lapel and relayed to the security booth.

‘You next, boy,’ said Kurt. ‘Same drill.’

Artemis complied, slouching on to the square. He barely raised his arms from his sides.

Butler glared at him. ‘Alfonse! Can’t you do what the man says? In the army I would have you cleaning the latrines for this kind of behaviour.’

Artemis glared back. ‘Yes, Colonel, but we’re not in the army here, are we?’

Kurt slipped Artemis’s pack from his back, rifling through the contents.

‘What’s this?’ he asked, pulling out a toughened plastic frame.

Artemis took the frame, unfolding it with three deft movements. ‘It’s a scooter, dude. You may have heard of them. Transportation that doesn’t pollute the air we breathe.’

Kurt snatched back the scooter, spinning the wheels and checking the joints.

Artemis smirked. ‘Of course it’s also a laser cutter, so I can break into your boxes.’

‘You’re a real smart alec, boy,’ snarled Kurt, stuffing the scooter back in the bag.

‘And what’s this?’

Artemis turned on the video game. ‘It’s a game box. They were invented so teenagers wouldn’t have to talk to grown-ups.’

Kurt glanced at Butler. ‘He’s a gem, sir. I wish I had one just like him.’ He rattled a ring of keys on Artemis’s belt. ‘And what are these?’

Artemis scratched his head. ‘Uh… keys?’