‘Just leave me alone.’

She commanded the carpet beneath her feet to carry her, then ordered it to flow faster, then faster again, until she was speeding along the east wing’s main corridor, artwork a blur on either side.

‘You know you do.’

The whispers followed her.

‘No. This is stupid.’

She raised her hand, and the carpet stopped flowing. Then she turned, faced the way she had come, and ordered it to carry her back toward the atrium.

For she was Luculenta Rashella Stargonier, and this was her home, where she was always in charge, and the most intimidating thing around was herself.

So what harm could an old plexcore do? Just how twisted and dangerous could its stored thoughts be?

She stopped a metre from the null-gel capsule, and stared at it.

FOUR

EARTH, 1926 AD

So here she was, in this long neo-Renaissance hall, beneath balconies forming galleries on either side. Black ironwork, globular white lights, a gleaming floor: everything polished and strong, suiting such a place of learning, for this was the Erdgenössische Technische Hochschule, where only a few decades before, Einstein himself had been a student. Now she, Gavriela Wolf, was here as an undergraduate to follow the same ambition: to determine how the universe worked, for the sheer joy of discovery.

This morning she had sent a letter to her parents, whose little shop in Sendlingerstrasse, in the heart of Munich, had been just around the corner from Einstein’s childhood home. It was only five years since the Wolf family relocated to Berlin.

Dear Mutti and Vati,

Zürich is such a pretty town, like our old München but with the broad flat lake, and such icy mountains all around. The trams, too, are cheerful as they wind their way up and down the cobbled streets. You would like to take your Sunday promenade here by the Zürichsee!

The road up from river level had been a steep climb, but those same trams she had written about were expensive, and the Polybahn funicular from Central would have been an extravagance. Still she had enjoyed the walk, listening to people greet each other with a gruff Schweizerdeutsch Grüezi !, smelling fresh-cooked Berliner doughnuts from a bakery, breathing cool air blown in off the glacial lake.

Two men in long brown work coats, one with mop in hand, were standing at the edge of the flow of students, watching them. It was like laminar flow in a river: moving fastest in the centre, diminishing to zero velocity at the edges. Except that these were people, not water molecules, and perhaps they could tell her where she was supposed to go.

‘Excuse me, please. Could you tell me where Lecture Theatre 3 is?’

‘Ah, with the thunder and lightning machine. The big metal lollipop.’

The incomplete sentences sounded rude, but perhaps her Hochdeutsch sensibilities were not appropriate. On the other hand, while the man might be uncertain about her Jewishness, her gender was undeniable. It was an attitude she had hoped not to find, not here.

‘Do you refer, sir, to a Van de Graaff generator that might be used for electrostatic investigations?’

The older man smiled.

‘She’s got you there. Sorry, miss, but my young colleague is unfamiliar with the name of the apparatus. Are you attending Herr Professor Möller’s lecture?’

‘Yes, that’s right.’

‘Then it will be our pleasure to help you, in order that you might get there on time.’

There was nothing unusual in the answer’s precision - the use of the subjunctive was an everyday courtesy - but in contrast to the younger man’s abruptness, it was reassuring. She nodded, memorizing the directions, and was gently formal in her thanks.

Two minutes later, she was settling herself among thirty young men in a lecture theatre that smelled of beeswax and chalk. She made no attempt to introduce herself; none of the men tried to talk to her. Since she was joining late, three weeks into the semester, the others would already have made acquaintance with each other.

No matter. She was here to learn.

In front was a bench, currently supporting the upright metal lollipop - not a bad description, really - that was the Van de Graaff generator. The vertical shaft contained a drive belt, and friction inside the metal sphere on top would generate an electrostatic charge of some considerable - and dangerous - magnitude.

Had Einstein sat in this room, or even in this seat?

My life is amazing. I’m so lucky.

She was poor only in her lack of money. The opportunities before her, and the family love behind her, were treasures that she had done little to deserve, however hard she worked. Neither her mother nor any of her earlier ancestors could have dreamt of being here, in Zürich’s finest centre of scientific learning.

Sunlight like pale honey shone through clear panes, highlighting the random dance of dust in the air, the Brownian motion that Einstein had shown confirmed the existence of atoms.

Professor Möller was broad-shouldered, with a large beard, a far-receded hairline but with a mass of fine grey-white hair, worn shoulder-length. He looked like the leonine illustrations in the Conan Doyle books that Gavriela enjoyed so much: Professor Challenger, scientist and adventurer.

Now, as the very real Professor Möller commenced his lecture, his gaze passed across the rows of faces, lingering on Gavriela no longer than on anyone else, as if unsurprised to find a young woman among his students. Nor did he look surprised when a door opened at the rear of the lecture theatre, and more people filed in, filling all the empty places behind the original twenty-seven students. Surely such lateness was a discourtesy? And could there really be this many first-year undergraduates? Some of them looked old enough to be faculty.

A young man with curly hair leaned towards her.

‘You’re in luck. This is no ordinary lecture.’

‘Oh. It’s my first day.’

‘I thought so, but that’s not the reason you didn’t know about this. I’ve been talking to some of the older students.’

That did not make complete sense; but most of the other first-years were looking as puzzled as she felt. So what was going on?

‘So, I wonder,’ mused Professor Möller from the front, ‘how many of you know what a Faraday cage might be?’

At this, some two-thirds of the room erupted in cheers, wolf-whistles and applause, more like a beer hall than a staid lecture theatre, while the first-years mostly looked surprised. Then two men in brown work coats - the pair that Gavriela had encountered in the hall - came in, bearing a big greasy-looking slab between them. They placed it down on the parquet floor next to the demonstration bench.

‘This is made of wax,’ said Professor Möller, ‘which, as you know, is a poor conductor of electrical current. At least, I hope I have that right.’

More cheers and laughter. Around Gavriela, some of the first-years were smiling, still puzzled but picking up the festive ambience. She thought of it as a form of resonance.

Then the two men left and returned with a smaller wax block, plus a large wire basket, at least a metre and a half tall: the kind of thing you might find in a park, convenient for visitors who had rubbish to dispose of. Its purpose here was beginning to dawn on Gavriela - surely the Herr Professor could not be serious?

He was starting up the Van de Graaff generator, so whatever the point of the preparations, everyone would soon find out. Then he beckoned forward one of the students: a burly, muscular fellow who stripped off his jacket at the Herr Professor’s request and rolled up his shirt sleeves. His revealed forearms were thick and strong-looking, his waistcoat snug around a barrel chest.