Fifteen more descents, and they were in a region of raw tunnels lit – and given habitable atmosphere – by ceiling fluorofungus, where dwelling-tunnels featured rows of hollowed-out al-coves that served as homes, and dumb-fabric hangings served as doors and interior walls, and the people were on the whole kind to each other, because this was a community strong in the face of poverty, where working together meant survival.

It was a good place to find a hospice, run by older folk with steady eyes and plain speech, who would not turn away the young girl-woman left at their door by a silent, hooded figure – her clothes far too rich for this stratum – who slipped away without greeting anyone. They helped Mandia inside with kindness.

Kenna moved on.

Other people were beginning to follow her, made suspicious by her clothing and lack of speech, so when the tunnel curved and her pursuers were out of sight, she broke into a run, moving fast and easily now, until she came to a high chamber formed of natural, raw rock in which a lava pool glowed and bubbled.

Dead end.

I will not fight them.

Let them wonder at her disappearance. She stared at the lava pool.

This will be fine.

With a neat motion, she dived into the molten lava and swam downwards through the hot, viscous liquid rock, not caring as her garments burnt away and the heat grew stronger, because this was freedom and wonderful. Something brushed against her – she felt angular flukes – and knew it for the one of the little studied native forms that lived inside the magma, and drew inspiration from the ease with which it moved here.

This world will be good enough.

Give it a millennium or two, she thought as she swam, and then she would move on. There was no hurry.

It would take time to become the person she needed to be.

THIRTY-SEVEN

EARTH, 1972 AD

Alone in her flat, Gavriela lay one slightly arthritic hand upon a project notebook and said to no one at all: ‘I always thought it would be the death of me.’ But here she was, sixty-four years old and mostly healthy, mostly retired, mostly enjoying life. A label on the notebook’s front cover explained the project’s name:

High

Energy

Interstellar

Meson

Detection,

Amplification &

Lensing

Lattice

It rarely spooked her these days, the thought that she had written out an identical description during wartime Oxford, scribbling in her personal notebook while asleep, something she had never done before or since. When Charles, her department head at Imperial, had first suggested she take over the meson research team and showed her the name of a project that Lucas Krause had proposed, he had actually been concerned for her health because of the blood draining from her face. But she had recovered and accepted the job, and nothing had come of it save for a wealth of readings concerning the behaviour of mesons from cosmic rays.

Their decay-time was affected by relativistic distortion, because their velocities were so high, providing one more validation of Einstein’s work: her hero, who had once played her nine discordant notes upon his violin, as an indication that they had more in common than a love of physics.

And Lucas Krause, whose team she had taken over when he left, was the same Lucas she had known as a student at the Erdgenössische Technische Hochschule, where Einstein had previously studied and even taught a little. There had been a brief period when she had taken to spending the occasional night at Lucas’s house – romance and physical love were never frequent features in her life – but he had finally returned to his estranged wife in Nebraska, on hearing that she was diagnosed with cancer.

That was five years ago, and Mary Krause was still alive and doing well, which Gavriela was glad of.

Inside the notebook was tucked a typewritten note from one of her Caltech acquaintances, someone she had met at several conferences and was a good contact, because he worked with Gell-Mann frequently. He said that a few people were talking about renaming the meson family members – K mesons, µ mesons and π mesons would now be known as kaons, muons and pions respectively – and asking what Gavriela thought of the notion.

She had not yet replied, uncertain whether her natural response would be perceived as European snobbery: that people should use Greek letters, along with Latin terms, as much as possible, and that furthermore there was no excuse for any physicist not to read the Cyrillic alphabet, and realise just how much Russian was comprehensible, especially since modern vocabulary so often resembled French or German.

Then she smiled, remembering Gell-Mann’s reputation as a polymath and polyglot who insisted on correct pronunciation of all foreign terms, and decided that she would write her reply exactly as it came to mind.

Earlier today, at half past eight, she had written a one sentence entry in her diary, after receiving an important phone call – fulfilling the reason she had got the Post Office to install a home telephone in the first place, as soon as she had heard that Carl was an expectant father.

Today I became a grandmother.

It was an echo of the day Carl was born, and more comforting than she had expected, the thought of continuity despite personal mortality.

(She had asked the engineer, when he was installing the phone, whether he had heard of a gentleman called Tommy Flowers. He had said no, then winked, causing Gavriela to smile. Within the next few years, thanks to the thirty-year rule regarding secrecy, the British public would begin to learn how her friend Alan had invented computers and how Tommy built the first, and incidentally shortened the war by two years at least, and perhaps made the difference between victory and defeat.)

The phone rang, one-two, one-two, left-right, left-right as she hurried to the hallway and picked up the receiver.

‘Is everything all right?’ she said, expecting Carl.

‘Most assuredly, old thing,’ came a familiar patrician drawl. ‘Why ever would it not be?’

‘Rupert.’ She closed her eyes. ‘I thought Carl might be calling from St Mary’s.’

‘He’s in church praying for a miracle?’

‘I mean the hospital. Alexander Fleming, penicillin, and now my first grandson,’ she said.

There was a short silence.

‘That’s really most excellent news, dear Gabby.’ He would not use her real name on a phone line. ‘Most excellent.’

‘Yes, it is,’ she said. ‘And an indication that I’m far too old to work for you, dear Rupert. Assuming you’ve a little job you wanted me to carry out.’

Another silence.

‘I do that, don’t I?’ said Rupert. ‘Ignore you unless I want something.’

That was disconcerting.

‘Are you all right?’

‘Yes . . . I was hoping we could meet up, not for work, and have a—’

‘Spot of tea,’ she said. ‘You do that as well. And I’d love to.’

‘You would?’ He sounded more cheery. ‘Fancy a stroll around the British Museum?’

‘So one old mummy can cast an eye over the others? I’d be delighted, dear Rupert.’

They agreed to meet in an hour, and then she hung up.

From the outside, the British Museum, like all the other major buildings in London, was a single massive block of soot, black and off putting. Inside it was airy, calming Gavriela down as she passed the Elgin Marbles – relics of one dead empire stolen by another, whose patrician classes were finally realising they had been trained to rule a quarter of the globe that was no longer theirs – and then stood in front of the dark stone Book of Gilgamesh, realising she was in the presence of the world’s first written story, not quite able to process the thought.