The next few hours required little from her but admiration and the occasional question. He was like a small boy showing off the finer points of his favourite train set. By the end of the afternoon, she knew more about the retail and rental of videos than she would ever have believed there was to know. But along the way, she had also picked up useful nuggets of information about the methods Tadeusz had adopted to launder his illegal proceeds through his legitimate businesses. Financial details had never particularly interested her, but even she could see how cunning his set-up was. She knew she was learning things that would help forensic accountants to unpick the financial morass of Tadeusz’s empire once he’d finally been arrested.

What was almost as important as the facts and figures that she’d garnered was the way their interaction was developing. Tadeusz found excuses to touch her at every opportunity; nothing overtly sexual, but something more than casual contact. Handing her a cup of coffee, his fingers would brush against hers. Showing her round the stores, he would place a hand in the small of her back or steer her by the elbow towards something of particular interest. Getting into the car, his knee would brush against hers.

Their conversation too was becoming more relaxed. Carol was surprised by how entertaining he could be. Funny and serious by turns, he made interesting what could otherwise have been brain-numbing. As they drove round Berlin, he amused her with anecdotes and fascinated her with gobbets of fact about the sights he pointed out. For minutes together, she forgot that she was working undercover, that this relationship had nowhere to go except betrayal, and actually found herself enjoying his company. It took an encounter with a video to ground her again in the reality of what she was doing. In one of the stores, Tadeusz showed her a special display. ‘Woody Allen films are big in this part of town, so we always make sure we have the full set available for rental and purchase,’ he’d said, gesturing towards the shelves. Zelig seemed to jump out at her, reminding her forcefully not to succumb to his charisma, to hold on to the memory of the viciousness that lay behind his easy charm and his sophisticated lifestyle.

At the end of the tour, he directed the driver to take them back to her apartment. As usual, he walked her to the door. But this time, instead of a courtly farewell, he gazed down at her and took a step closer. Carol had to make an instant decision. Break the moment and walk away or draw him further into complicity with her. It was, she knew, a key moment. She stood on tiptoe and brushed a kiss against the corner of his mouth. ‘I’ve had a lovely afternoon,’ she said softly.