'Please… You and I know how this works.'

'Let's just cut to the chase, then,' Thomas said. He knew he was speaking out of anger, that he needed to keep his trap shut, but the words easily outran his horse sense. 'What can you tell us, Dr Mackenzie?'

Mackenzie leaned back into his seat, his appraising look shocking for its sudden seriousness. He reached out and withdrew another cigarette. One for the road, as it turned out.

'You know what?' he said, squinting as he ignited it. 'Now that I think about it, precious little.'

'Let me guess,' Sam said. 'It's all classified.'

A burst of infectious laughter, framed in roiling smoke. 'Not at all, Agent Logan. Not at all'

'Then what's the problem?'

'Well, agent, here's the thing. I genuinely like Neil Cassidy. He's the most brilliant man I've ever known.' His eyes became round with apologetic surprise, as though he'd just stumbled across a disconcerting fact. 'And I've decided that I don't quite like you…'

'But don't you feel betrayed?' Thomas blurted. How had things turned south so quickly?

'Exactly,' Sam added. 'If any of this gets out, you could find yourself without a career, or even worse.'

'Perhaps that wouldn't be such a bad thing,' Mackenzie replied without missing a beat. 'But I think you and I know the chances of that are pretty slim.'

Thomas looked to Sam, not quite sure what to make of this last comment. Just who was talking shop with whom? But she simply stared at the man, as if weighing some kind of dreadful decision.

Without warning, Dr Mackenzie was on his feet, smoking no-hands, stuffing his Winstons into his suit jacket.

'Well, I'm off,' he said, speaking as though they had just shared a plate of fish and chips. He turned on his heel and made for the door.

Thomas was dumbstruck. 'Mackenzie!' he cried out.

He paid no attention to the other faces in the bar, though he was sure they had all turned toward him. Mackenzie spun, crooked his face forward attentively, waiting to hear what he had to say. 'You do know that'—Thomas glanced nervously at the other patrons—'people, real people, could be hurt if you walk out on us?'

Slow blink. Sad smile. And a response that completely evaded his question.

'Ask yourself, Professor Bible, if you're so certain that the masses have no hope of grasping the Argument, then why is our friend Neil making it? He never struck me as particularly optimistic.'

The old man turned to hustle out the entrance, but paused, dragged around by a wagging finger.

'Oh, and Professor Bible…'

'Yes?'

'You should know that I actually envy you, in my way.'

'How so?'