As he followed Farzan out of the cloistered quadrangle and into the town, he couldn’t help but wonder about the nature of the gossip circulating amongst Vidor’s students and colleagues. The words ‘nervous breakdown’ were surely being bandied about. A nonsense term in medical circles, but a handy description when speaking to a layperson. He glanced at the young man by his side, brow furrowed, head bent, likely devising an algorithm to explain the impenetrable processes governing the brain. More philosopher than scientist, Gessen held fast to his belief that the human mind, unfathomable in its mystery, would forever resist being described by a series of equations.

They threaded their way through a busy street thronging with shoppers and students weaving like mad on their bicycles, before ducking into another courtyard where their footsteps rang out pleasingly on the stone. Tables were set out in a sunny corner, perhaps for the last time this year, before the cold weather drove everyone indoors. The tables were empty, except for the one closest to the cafe where a girl in a long skirt and knitted cardigan was bent over a book, oblivious to their presence.

‘What can I get you?’ Gessen asked.

‘No, you are my guest.’ Farzan’s voice was firm. ‘They have excellent coffee here. Or tea, if you’d prefer.’

Though a confirmed coffee drinker, Gessen decided on tea. After the two cups of excellent tea he’d drunk at Vidor’s kitchen table, it seemed unwise to make the switch to a more bitter brew.

While Farzan ducked inside to get their drinks, Gessen surreptitiously studied the girl at the table nearby. Intent on her book, she hadn’t looked up when he and Farzan approached. If he were a young girl, dreaming away the afternoon, he might have been dazzled by Farzan’s film star looks, but she clearly had more serious pursuits on her mind. He tried, and failed, to catch the title of her book.

Farzan returned with a pot of tea and a plate of biscuits and scones. All very English, as one might expect, but now that they were out of the lab and in the fresh air, Farzan’s nervousness had only grown. When he picked up his cup, his hand shook, and his eyes flicked worriedly at the girl seated a few metres away. Twice he turned his head to glance behind him.

‘It’s terrible what happened to Professor Kiraly,’ he said, stirring sugar in his tea. ‘Everyone is worried about him.’ Farzan scanned Gessen’s face as if hoping to find clues to the fate of his advisor.