The journey passed more quickly than he would have believed possible. Running over his plans always shrank time, he’d found that out in the past few months. The images of what he would do to Marie-Thérèse Calvet were better distraction by far than any kind of in-car entertainment. Before he knew it, he was on the outskirts of Köln, the main artery from Koblenz delivering him right to the inner ring road, a short distance from the university. He checked his street map and navigated his way to Robert Koch Strasse. From there, it took him only a couple of minutes to reach the institute building. Luckily, Calvet had been efficient with her directions, and he didn’t have to stop and ask anyone the way to her office.

The corridor wasn’t quite empty. A couple of students were walking towards him, deep in conversation. With the self-absorption of the young, they didn’t even glance at him as he passed, his head angled down and away from them to minimize the chances of them being able to describe him afterwards. After Bremen, even so casual an encounter was enough to set his pulse fluttering and quicken his breath.

He counted the doors. Fourth on the left, she’d said. He stopped outside the plain wooden door and read the nameplate: DR M-T CALVET. He took a deep breath and held it, trying to force his previous state of calm to return. He raised his hand and knocked once, firmly. ‘Come in,’ he heard, the high pitch of the voice slightly muffled.

He opened the door and led with his head, his smile stretched to breaking point. ‘Dr Calvet? I’m Hans Hochenstein.’ He continued into the room, fixing his eyes on the woman emerging from behind the desk. She was tiny. She couldn’t have been more than five feet tall, with a fine-boned gamine face. Her chestnut hair was cut close to her head, and she wore an outfit of smartly casual top and capri pants, which he recognized from the old movies Gunther loved to watch as an homage to Audrey Hepburn. Unfortunately, he thought, she didn’t have the eyes to carry it off. Dr Calvet’s dark eyes were small, set close against the narrow bridge of her nose, making her look slightly cross rather than carefree and vulnerable. She held out a slim, bony hand to him, and he took it gently, enveloping it in what suddenly felt like an excess of damp, sweaty flesh.

‘I’m pleased to meet you, Mr Hochenstein. Please, take a seat.’ She gestured towards a pair of armchairs on either side of a wall-mounted gas fire.

He would have to move fast because there was no knowing how long they would be left alone. In order to get behind her, he stepped to one side and gave a courteous bow. ‘After you, doctor.’