‘That’s easy,’ she said. ‘The callousness. The way he engineers all this without ever getting his hands dirty. I can’t get rid of the image of that dead dealer, lying on the steps of the police station with his brains on the pavement. And Radecki sitting in his expensive Charlottenburg apartment, sealed off from all the shit, listening to Verdi or Mozart, as if it wasn’t connected to him. That’s what gets to me.’

‘So every time you feel the tug towards him growing too strong, summon up those two contradictory images. That’ll ground you in what you’re there for.’ He dropped her hands and stepped back. ‘You can do this, Carol. You’re good enough. You’re strong enough. And you’ve got something to come back to.’ He held her gaze. For the first time since they’d met, he was making her a promise he thought he just might be able to keep.

If Dr Margarethe Schilling had known she was experiencing her last afternoon alive, she would probably have chosen to spend it differently. Perhaps a reprise of their favourite woodland walk with her lover. Or perhaps round her kitchen table with her closest friends, good food and wine and conversation flowing freely. Or, most likely, playing a computer game with her eight-year-old son Hartmut. Even her hardhearted bastard of an ex-husband wouldn’t have refused to vary the conditions of Margarethe’s contact time with her son if he’d known she was about to die.

Instead, unaware of what lay ahead of her, she considered her hours in the university library well spent. Her main academic interests lay in the psychological effects of religious belief systems, and a recent visit to the Roman museum in Köln had triggered off some ideas relating to the effects on the indigenous population of the imposition of Roman gods following their occupation of Germany. She was also intrigued to see if the collision between two contradictory religious systems had had any modifying influence on the Roman occupiers.

Her research was still at the embryonic stage where she had to accumulate information before she could begin to formulate theories. This was the tiring, tedious part of the process; hours spent in dusty archives, following trails that dead-ended as often as not. She had heard of researchers who had actually been infected with ancient illnesses as a result of poking around among materials that had barely been disturbed for centuries, but so far nothing that dramatic had ever happened to her.