She decided to ring her friend Sandra. Back in Berlin, Norah would simply have dropped in on her; she’d lived only a few streets away. And in the years before Berlin, Norah would have numbed the thought with drugs. But all that was a thing of the past; she’d been clean for ages.

Sandra didn’t pick up. Norah let her eyes wander over the moulded ceiling, the spotless parquet, the cardboard boxes, her few belongings—and all of a sudden she noticed a buzzing sound. She felt it rather than heard it, somewhere between her diaphragm and her breastbone, and it was a moment before she could put a name to it. These last few years she’d been alone so little she’d almost forgotten the feeling. It was loneliness—deafening loneliness.

She had to get out. Out into life. That always helped when gloom threatened to descend. Norah glanced at her phone and wondered who else she could ring. In Berlin it would have been easy to find someone who’d go out for a drink with her, but it was different in Vienna, where there was really only her best friend Max and his husband Paul—and her old mate Tanja, of course, but she was in Hamburg just now. Max had been thrilled when Norah had told him she was moving to ‘his’ city. She tried his number. Voicemail.

She thought of going out by herself, but didn’t have the nerves to face the comments and pick-up lines that a woman alone in a bar would be bound to attract. Her chest felt as if it were about to burst. She sat down, checked Facebook and Twitter, and tweeted.

Anyone else out there who can’t sleep?

#sleeplessinVienna

She waited for a few minutes, but no one replied.

Then she gave up and zapped her way through the TV channels until she found a documentary about indigenous foxes that she liked the look of.

Norah sat up with a start. She couldn’t have slept for long—the same documentary was still showing on TV—but she felt that vague confusion that comes over you when you wake from a deep dream. Dazed, she sat up, wiping sweat from her forehead. Floorboards creaked overhead; her upstairs neighbour was still awake. What was her name again? That’s right, Theresa.

How strange life was. Norah had left everything behind to start over in another country, and the past had caught up with her on her very first day in the new city.

Rubbish! It was only a stupid coincidence that her new neighbour looked the way she did. Didn’t people say that everyone has a doppelgänger somewhere? And how often in the past years had Norah thought she’d seen her, in a passing train, an airport lounge, a pavement cafe?

But it wasn’t only the similarity between Theresa and her that had made Norah think of her on and off all day. It was also the words spoken by the woman with the begging bowl.

On February 11 you will kill a man called Arthur Grimm in the Prater. With good reason. And of your own free will.