Maintaining a low profile was a priority. I had no idea how widely circulated my photograph had been at an official level, or if I was publicly associated, visually, with the ambush in La Fée Verte. There was, though, one thing to take comfort from: unlike in Paris and London, CCTV coverage in Tel Aviv was at best patchy. Before I’d left France, Baaz had gone on his own special mission to replace my wardrobe. The ripped black kit I’d assembled before the dive into the tunnels had been replaced with new black jeans, black sneakers and a short black leather jacket. Baaz liked black. I liked Baaz.

I stuck my arm out, and hailed a cab to the university.

‘Ken, ma bishvilkha?’

‘Shalom,’ I replied, trying not to sound annoyed. I’d been standing in the doorway, clearing my throat and tapping my foot, while the woman who I assumed was the faculty secretary finished a convoluted and – as far as my shaky Hebrew could make out – entirely personal phone call. ‘I’m here to see Professor Levy.’

‘Rachel?’ I nodded. ‘She isn’t …’ She stopped herself abruptly and sized me up. ‘What is your name, please?’ She spoke in careful American-accented English.

‘Lazarus,’ I replied. ‘John Lazarus.’ She looked at me, waiting for me to continue. ‘From MIT,’ I added – as if that explained everything. She pursed her lips and raised her finely plucked eyebrows.

‘And did you, do you, have an appointment, Mr …’

‘Doctor,’ I corrected her.

‘… Doctor Lazarus?’

‘Yes,’ I lied. ‘I do.’ I checked my watch ostentatiously. ‘In five minutes, to be precise.’ I gave her a quick smile. It wasn’t reciprocated.

‘I see.’ She pivoted in her office chair, turning her back fully on the computer screen she’d been facing when I walked in. ‘There is nothing in her diary,’ she said. ‘And your appointment is here, in the faculty?’

‘Yes,’ I said. ‘My assistant called last week. I leave for Boston tomorrow.’

She turned around again and looked at me closely, as if making her mind up about something.

‘Please wait.’

I didn’t doubt she meant it. I looked around and saw an empty chair behind the door. I sat down. The secretary returned to her screen and tapped away at the keyboard before lifting the receiver on the office phone next to her. She spoke quickly, quietly, and the only words I could make out with any certainty were my assumed name and ‘Rachel Levy’.

The Kolymsky School of Computer Sciences – part of the Faculty of Exact Sciences – was based in a low-rise four-storey building at the heart of the university campus. It was the kind of place that should have inspired reverence and hushed tones, awe at the seemingly impossible problems being solved behind closed doors. All it inspired in me was an uncomfortable mixture of irritation and nervous expectation.