Butler ignored the pandemonium, concentrating on his right hand. Or rather where his right hand had been a second earlier. Just before Artemis fizzled into another dimension, Butler had managed to get a grip on his shoulder. Now the disappearing virus had claimed his own hand. He was going wherever Artemis had gone. He could still feel his young charge's bony shoulder in his grip.

Butler fully expected his arm to vanish, but it didn't. Just the hand. He could still feel it in an underwater-pins-and-needles kind of way. And he could still feel Artemis.

'No, you don't,' he grunted, tightening his invisible grip. 'I've put up with too much hardship over the years for you to disappear on me now.'

And so Butler reached down through the decades and yanked his young charge back from the past.

Artemis didn't come easy. It was like dragging a boulder through a sea of mud, but Butler was not the kind of person that gave up easily. He planted his feet and put his back into it. Artemis popped out of the twentieth century and landed sprawling in the twenty-first.

'I'm back,' said the Irish boy, as if he had simply returned from an everyday errand. 'How unexpected.'

Butler picked his principal up and gave him a perfunctory examination.

'Everything is in the right place. Nothing broken. Now, Artemis, tell me, what is twenty-seven multiplied by eighteen point five?'

Artemis straightened his suit jacket. 'Oh, I see, you're checking my mental faculties. Very good. I suppose it's conceivable that time travel could affect the mind.'