After the obligatory introductions, Sam slid against the wall and Thomas settled next to her. She laid the tips of all ten fingers on the manila file folder she had placed before her. It seemed quaint, like something from the innumerable crime movies Thomas had watched as a child.

I'm actually part of an investigation… The FBI for chrissakes!

'My,' Mackenzie said, tilting his head in Sam's direction, 'aren't you a striking beauty.'

Ordinarily, a statement like this would have sounded sexist, but for some reason, his age and festive disposition seemed to render him exempt. It was like he had a 'dirty old joker badge' or something.

Rather than blush, Sam smiled and looked down. His expression mild, Mackenzie retrieved a pack of Winstons from the inside pocket of his suit jacket. The lighter he seemed to conjure from nowhere.

'A nasty habit I've never been able to shake,' he explained in the midst of billowing smoke. 'Lucky for me, this place casts a blind eye.'

'A speakeasy for smokers,' Thomas said, finding himself, despite all his earlier apprehensions, quite disarmed. Mackenzie, he realized, was a classic rogue, someone who used charm and impish good humor to run roughshod over even the most exacting social niceties.

'For every Prohibition,' the old man declared, 'there are a thousand blind eyes, I assure you.'

Sam raised her eyebrows, pursed her it-girl lips. 'I do work in law enforcement, Dr Mackenzie.'

'I suppose,' the impish old man replied. 'But then you need me far more than otherwise, Agent Logan.' He looked at Thomas, shot him a friendly blink. 'Game Theory 101,' he said. 'Strike, or be struck.'

Sam leaned back from the wires of curling blue smoke, clearly annoyed. Smiling, Thomas reminded himself not to be taken in by the old charmer. Given what this man did for a living—he quite literally 'hacked' brains (in both senses of the word)—there could be little doubt that he, like Neil, was some kind of sociopath. Lacking the circuitry for the social anxieties that plagued everyone else, he doubtlessly found putting people at ease quite effortless. A former colleague of Thomas's had spent a better part of her career studying psychopathy. The biggest challenge, she had said on more than one occasion, was immunizing her research assistants against their charms.

Sam pressed on. 'What exactly was the nature of your work, Dr Mackenzie?'

'I'm afraid that's classified.'

The expected answer. Sam continued without missing a beat.

'It says here that you were Dr Cassidy's immediate subordinate—his second-in-command, in effect. Is that true?'

An apologetic look, mawkish because of the agility of his face. 'I'm afraid that's classified as well.'