A memory flashed through his mind. One day last September, before things had turned violent with Attila and his henchmen, Balthazar and Anastasia had been sitting in her car when he had threatened them.

‘The Duchess and the Gypsy. A real Hungarian scene. Someone should paint you both,’ Attila had said, with a smirk on his face.

Still, it was quite a sharp line. The Duchess and the Gypsy. One descended from a line of noble aristocrats and the other from a dynasty of pimps. Could that ever work? Was she even interested? Perhaps, he thought. He remembered how she had blushed when they were joking about Ilona Mizrachi, the times when their eyes had met, the way her leg had brushed against his in her office. Or maybe Anastasia was just being polite and friendly, overcompensating a bit like many liberal-minded Hungarians, to show she wasn’t prejudiced? Sooner or later, he knew, he would find out.

Meanwhile, he had something more pressing to deal with. He needed to speak to Alex. Text messages were generally fine – Alex’s generation seemed to live by them – but he needed to hear his son’s voice. Partly because that was more intimate than staring at characters on a mobile screen, but also because he could hear the timbre and tone of his voice, and sense Alex’s emotions and mental state. Now that Sarah had started playing power games again with his access to his son, he made sure to speak to him every day.

Balthazar glanced at the makeshift Holocaust memorial as he walked through Liberty Square. A young woman with pale-blond hair and wire-rimmed glasses was poring over the testimonies in the plastic folders that were pinned to the rope. He walked over for a moment and watched a tour guide point at the statue of the eagle swooping over the Archangel Gabriel, explaining how inaccurate the imagery was, that Hungary had been many things during the Nazi occupation, but an innocent angel was not one of them.

He was about to walk away when one of the testimonies caught his eye. The photograph and the testimony were very clear – the photograph especially so. He walked over to take a closer look. Miklos and Rahel Berger had been attractive couple, he thought, clearly devoted to each other. The names meant nothing to him but there was something about them that looked almost familiar – why was that?

He read through their brief biography until the last line – Tragically, they were too trusting – then his telephone rang, breaking his line of thought.

He took the call – it was Gyula, a contact of his in the municipal vehicle registration department, ringing with information about the number plate Balthazar had photographed at the Librarian’s funeral. Balthazar had not made an official request to check the plate, as that would be logged and go through the system. Instead he had used every Hungarian’s favourite entranceway: the kiskapu, the little gate where a contact would do an unofficial favour, one to be banked for future credit.

‘That Merc’s registration number you asked me about. I checked it,’ said Gyula.

‘And?’

‘It’s a company vehicle, registered to Nationwide. There’s no more information, no name in particular, just the usual company details.’

‘Thanks, Gyula. I owe you one,’ said Balthazar and hung up.

Distracted by the call, he turned away from the memorial, and headed down Oktober 6 Street. The drizzle had stopped, the wind now just a breeze and the air pleasantly brisk before the chill of the night set in. The building on the corner was a former communist-era office building, now a bank, covered in pale marble. At first glance it looked yet another identikit homogenous structure. But Budapest could still surprise and delight. On its side the architects had preserved a giant fresco of two-metre-tall, sturdy, jolly peasants leading a horse as they brought in the harvest.

So what was his harvest with this case? It was now Friday afternoon. Elad had been missing since Wednesday evening. Balthazar had checked with Eva neni earlier in the day. There was still no sign of him or any messages. She was frantic with worry.

At least he now knew that it was a Nationwide vehicle that had been following Elad. But would Karoly Bardossy really be that unconcerned about leaving a trail of images and evidence that led back to his company, then arrange to kidnap Elad? Especially when he was such an obvious suspect? Maybe Karoly thought his wealth and connections made him invincible. Perhaps he was, for the moment. But nothing lasted forever, especially in Hungary, and Karoly would know that. Why bring so much heat down on yourself?

And what was the connection with the gunfire on Klauzal Square? That was a warning, but from whom? Had Karoly Bardossy, or someone at Nationwide discovered what Vivi had found on the decrypted memory stick? And if they had, then how? Vivi had not told anyone about the contents of the memory stick, except him and Anastasia.

And all of this against the backdrop of the forthcoming visit of the Israeli prime minister in three days – and Ilona Mizrachi’s not very subtle fishing expedition at the Boho Bar. Hopefully, Geza Kovacs would be able to help make sense of this – if he was ready to talk about whoever was paying him.

For a moment Balthazar felt a familiar, unwelcome pressure on the back of his neck as he walked down Oktober 6 Street. The kind of pressure that signalled someone was watching him, perhaps even following him. Then it faded and he was suddenly hit with a burst of nostalgia, displacing everything else.

This part of downtown, the heart of District V, was home to Central European University where Balthazar had for a while been a PhD student. He strolled past the spacious Israeli-owned falafel bar where he had spent so many lunchtimes experimenting with the menu of unfamiliar dishes, and Bestsellers, the English-language bookshop whose friendly owner, Tony, was always happy to recommend his latest choice – and which had always proved enjoyable.

A clutch of students exited one of the CEU buildings on the other side of the road, a 1970s communist-era horror of smoked glass and concrete in the middle of a row of elegant Habsburg apartment houses. Their laughter and happy chatter carried across the street as they discussed where to go for a drink. For a moment Balthazar envied them, not just their youth, but the world of possibilities that they would soon face, where decisions were still to be taken, of life paths that could still go in a myriad of directions.

And what of the decisions he had taken? He could have had that life, had he wanted, spending his days in the not very arduous world of academia, surrounded by the young, smart and quite often beautiful.

All the doors had been open. His supervisor in the history department, an amiable New Yorker of Hungarian background called Misha Fekete, had made it clear very quickly that a comfortable career was in easy reach if he finished his PhD. Misha was well connected in academia. There was talk of scholarships to Oxford or Harvard, tenure at CEU. The Holocaust was thoroughly documented, and still pored over by academics around the world. The Poraymus was neither.

Balthazar had been in prime position to contribute to the study, even build a new discipline – and who better to do that than a Gypsy historian? Yes, there was the suspicion that he would be a disz-Cigany, a decorative, token Gypsy, in place to highlight the liberal credentials of those around him, rather than on merit. But really, so what? Everyone needed a patron – at CEU it would have been Misha Fekete; at the Budapest police he had Sandor Takacs.

To himself at least he could be true. Balthazar would never tell Sandor, or indeed anyone, but one reason – perhaps the real one – he left academia was the prospect of seeing Sarah every day at the CEU building, in the café, the lifts and the libraries. Losing his wife – and to another woman – had been a hammer blow, even a humiliation. Perhaps he should have listened to his parents’ warnings before the wedding – Gypsies and gadjes, their culture, their values were too far apart for a mixed marriage to ever work. Gypsy women did not leave their men.

His family had been stunned – even more so when he had eventually explained that Sarah had moved in with a woman. Every one of his relationships after Sarah had seemed to prove that true: Eniko had left him, for reasons he still did not fully understand, and now Kati too. Still, he had a son, handsome and smart, to whom he was growing closer as he grew, and that was something that made everything else worthwhile.

Balthazar turned the corner from Oktober 6 onto Zrinyi Street. The narrow pedestrian thoroughfare led onto St Istvan’s Square and the Bazilika, which housed the right hand of St Istvan, Hungary’s first king. He paused for a moment to take in the view of the church. Dusk was falling now and the Bazilika looked magisterial, its giant domed roof and two towers softly illuminated against the darkening sky, streaked with grey.

The wind picked up and the pressure on the back of his neck intensified.

This time he took notice. Was he being followed? He stopped for a moment, glanced at his watch, then looked up and down the street as if looking for someone. The pedestrians flowed around him: commuters hurrying home for the evening from their jobs in the nearby ministries, a few hardy tourists and the CEU students.

Nobody stopped, but that did not necessarily mean anything. A professional team might be following him in a box, with one tracker behind him, another to the side and the third in front.

He really needed to call Alex, and also message Anastasia the address that Attila had given him. But first he needed to see if he was being watched. Surveillance detection drills used all sorts of techniques to see if someone was following: taking the suspected watchers into a chokepoint, like an underground passage or a staircase, to see if they followed, getting on a bus or train then getting off at the very last moment, going into a department store and moving up and down between floors or simply stopping and checking as he was now.

Sometimes it was necessary to lose watchers without them knowing that they had been detected. At other times it was more useful to get up close and personal, to let the watchers know that they had been busted. This, he sensed, was one of those times.

There were six benches spread out along Zrinyi Street. Balthazar sat down on the one in the middle, which faced an art gallery on the other side of the street. He took out his phone and scrolled through the numbers, as though he was looking for someone’s contact details, but was actually watching the street with a sharp, intense focus. Several tables stood outside a café on the other side of the street, a few metres further towards the Bazilika.

Nobody sat down next to him – that would be a very amateur move. But among the crowd two people stopped walking. One, a woman who looked to be in her late twenties, suddenly became very absorbed in the painting on display in the window of the facing art gallery.

She wore a grey skiing jacket and had black hair under a black baseball cap and stood with her back to Balthazar. A few yards further up the street, a man of similar age in a brown skiing jacket, stopped, turned and sat down at the café’s outdoor table. Both had white wires trailing from their ears.

He watched them for a moment. Neither caught his eye. None of this was evidence that he was being tailed. Lots of twenty-somethings had Apple earpieces and wore skiing jackets in winter.

Balthazar looked again at the young woman and the man at the café table. Where were they from? There was something about them, their gait, the way they held themselves, their alert, hyper-confident manner, that made him think they were not Hungarian. Were they British or American? He didn’t think so. In any case there was no reason for the British or the Americans to be following him. There was a reason for another country’s operatives to be doing so.

A waitress appeared at the table and handed the man a menu. He held it high to his face. Balthazar dropped his head, apparently absorbed in his telephone. In reality he was looking across the street. The man glanced at him over the edge of the menu. The young woman was still staring inside the art gallery. The door opened and an assistant invited her inside. She declined and her head turned rightwards for a fraction of a second at the man sitting at the café table before returning to the gallery window.

Balthazar smiled to himself.

The man, or the woman? The woman, he decided.

He walked across the road and stood next to her. ‘Nice paintings. I like the one in the corner,’ he said, pointing at a colourful portrait of an elderly lady looking out of a window at the sea. ‘She looks like she knows someone is watching her.’

The young woman took a half step to the side, glanced at Balthazar, not quite able to keep her irritation from showing. ‘If you say so.’

‘I do.’ He tilted his head to the side, looked intently at her. She had brown eyes, full lips and a plump face. ‘You know, you really look like a friend of mine.’

She stared at Balthazar, her eyes darting sideways for a moment. ‘That’s nice. But I’m waiting for someone, so thanks but no thanks.’

‘I’m sure you know my friend,’ said Balthazar.

‘I doubt it. Please stop bothering me, or I will call the police.’

Balthazar took out his wallet and showed his identity card. ‘I am the police.’

She stepped further away. ‘I have no idea what you are talking about. Please leave me alone. Or I will shout for help. There are lots of people here.’

‘I don’t think you are going to do that. But I’ll tell you my friend’s name anyway; that might help. She is called Ilona Mizrachi.’

The young woman stiffened and a pink flush crept up the side of her face.

‘Give Ilona my regards,’ said Balthazar.