Evadne was looking up with an expression of frustrated disappointment. ‘Don’t take my hand,’ she said to Kingsley. ‘We can run faster if we don’t.’

‘Yes. Good point. Ready?’

She rolled her eyes and then she was gone. He had to sprint to catch up to her.

For a moment, Kingsley had the hope that they might be getting away unnoticed, but then a shout went up. He increased his efforts and leaped into the alcove to join Evadne. She was crouching and examining the rotating pyramid.

Kingsley left her to it. He positioned himself on the second stair of the alcove, between Evadne and the three Neanderthals who were running towards them. ‘Soon would be best,’ he called over his shoulder.

‘I’m doing the best that I . . . Oh!’

Kingsley didn’t like the sound of that. He liked even less the flare of warm light that rolled over his back, briefly illuminating the hall and making the trio of approaching Neanderthals stop dead.

He risked a glance over his shoulder. Evadne was standing there, staring at her open hand. ‘I had a vial of phlogiston. It ate it.’

‘Now it’s rotating faster.’ Kingsley turned back to see the Neanderthals had resumed their advance, but they were more cautious, even hesitant, spreading out as they neared.

Another flare of light washed over him, then another. The satisfied ‘Aha!’ from behind made him look over his shoulder again, and while he took in the fact that the tetrahedron was whirling much faster now, it also gave the Neanderthal on his left time to charge.

Kingsley thought he’d been hit by an omnibus. Two omnibuses. The entire London fleet of omnibuses. He landed with the Neanderthal on top of him. As well as having all of the air driven out of his lungs, his head cracked hard on the marble plinth.

It was as if he’d taken a step sideways from the universe, which had then had all of the colour shaken from it, while all of the sounds had been passed through layers of wool to make them familiar in shape but utterly meaningless. Bright lights hung in his vision, which he vaguely thought appropriate. He saw more Neanderthals rushing and leaping over him. Four backed Evadne against the wall of the alcove. Her sabre flashed. More flaring light. A giant bell was tolling at the back of his skull and had been for some time.

He closed his eyes and it all went away.

‘We’re back home.’

Kingsley found he was lying down. He went to sit up, but he was made of rubber and couldn’t. He made an effort to show he was coherent by repeating part of what Evadne said, but chose poorly: ‘We’re?’

Evadne loomed over him. She’d lost her coat, he noticed, but he did like the way it showed off her dove grey dress with the red ruching. Her arm snaked under his shoulders. ‘Here, drink this.’

He sipped at the water and had a feeling he should admire the mug, which was made of gold, but he couldn’t raise the energy. She studied him with concern. She looked tired, but determined and entirely, inappropriately fetching.

He was about to ask the standard orientating question when he took in the glazed blue bricks. They haven’t invented a prison I couldn’t break out of, he thought, but I can’t stop them putting me back in it.

‘You’re going to feel nauseated, I’m sure. That was quite a knock on the head.’

It came back to him. He touched the back of his head and regretted it, but his astonishment and relief made the pain bearable. ‘It worked? The Time Manipulator?’

‘In a manner of speaking. Two Neanderthals tried to take me, but one of them put his hand on the tetrahedron. He vanished.’

‘He activated the machine?’

She grimaced, an altogether wonderful sight. Kingsley wondered if she’d ever had her portrait done. ‘It stopped glowing after he disappeared, so it would seem. But I have no idea where he went. I couldn’t see any way to calibrate it, no controls to set, nothing. It’s frustrating.’

‘I imagine that’s how our missing Neanderthal must feel. He’s probably sitting around in the Renaissance thinking what he’d do if he had his time over again. So to speak.’ He sat up, gingerly. ‘So we’ve travelled back in time a few hundred years, then forward in time by the same amount. Quite an achievement. And then there’s freeing a company of abducted children and avoiding the clutches of the Immortals.’

‘I’d love to be in a position to marvel over our achievements,’ Evadne said. ‘I have a few people I’d like to consult about the mechanics of our time travelling. However, we have more pressing issues. Escaping from here, for one.’

‘Wait. You said we didn’t use the Time Manipulator. How did we get back here if we didn’t?’

‘We were taken through time in the not so gentle embrace of the Neanderthals.’

‘I beg your pardon?’

‘The sparkling belts they wore weren’t fashionable accoutrements. They were part of their time travel equipment. One of them slung you over his shoulder and one held me tightly. The others surrounded us in a ring, then they linked their belts with fine chains so they were all connected. The black-bearded one took out two brass marbles. He fitted one into a slot on his belt, and as soon as he inserted the other into a different slot, we snapped out of 1666 and ended up here.’ She gave a small laugh. ‘Our arrival did some damage to their machine, I’m pleased to say.’

‘What? How?’

‘The argument was about someone forgetting to allow for the fact that you and I had temporal potential energy as well as our captors.’ Absently, she made juggling motions with her hands. ‘We snapped back with too much force and the dampeners hadn’t been set to compensate, apparently. We’ve burned out some sensitive bits and pieces. They’ll need remanufacturing.’

‘I suppose they took your satchel.’

‘Most greedily. And my sabre and pistol.’ She cocked her head. ‘Are you all right? You don’t have a fractured skull, do you? Let me look at your eyes.’

‘I don’t think so. Just a bump and a nasty headache.’

She let go of the sides of his head. ‘Your eyes look well enough. Your concussion must be minor.’

‘You have medical training – no, don’t tell me.’ He held out a hand in the manner of a traffic policeman. ‘Clarence has. He’s an amateur brain surgeon.’

She opened her mouth, closed it again, reconsidered, then said: ‘I note your heavy-handed irony and I’ll endeavour, in future, not to bore you with Clarence’s achievements.’

‘He isn’t, is he?’

‘A brain surgeon? No, not amateur nor otherwise. He has worked on a voluntary basis, however, with doctors treating the poor and indigent.’

‘I find it hard to believe.’

‘I beg your pardon?’

‘Achieving so much in one lifetime. Extraordinary chap.’

She looked at him closely. ‘He’s very busy.’

‘So it would seem.’ He stretched. ‘We’re in the Neanderthals’ prison, aren’t we?’

‘Freshly dusted for our convenience. What is it?’

‘What is what?’

‘What is it you’ve just thought of? You went all squidgy there.’

‘Squidgy?’

‘You drew in your cheeks, narrowed your eyes, and moved your jaw from side to side. Something awkward or embarrassing has just occurred to you.’

Kingsley put a hand to his chin. ‘I did all that?’

‘You did.’

‘And you noticed and you have a name for it?’

Evadne hesitated and nipped around the question in an expert flanking manoeuvre. ‘What was it?’

‘I don’t think we’re going to be here long. Otherwise they would have put us in two cells.’

‘Ah.’ She looked around. ‘I’m not sure if the Neanderthals think like that.’

‘You’re right. I’m not sure what Neanderthals think at all.’ He hesitated. ‘Have you ever talked with one?’

‘Kingsley, until the last few days I’d never even seen one. They’re among the most elusive of Demimonders.’ She poured herself a cup of water and drank it all. ‘You’re right, of course. I have no idea what they’re thinking, apart from that they want to wipe us out or possibly eat us. And what we’ve just been through has shown that they can do what they’re planning. I’d say they simply don’t have enough power yet.’

‘If we can stop their plans to destroy humanity, I’d like to see what makes them tick.’

‘What makes a tiger tick?’

‘They’re people, not animals.’ Even as he said it, he wondered if perhaps the Neanderthals were closer to the wild than Sapiens were – and if perhaps this could shed some light on his particular halfway state.

‘Are they? Are they any different?’

Kingsley shrugged. ‘You’re different. I’m different.’

Evadne stared at him. She blinked, then stared again. Finally, she sat back and crossed her arms on her chest. ‘You, Kingsley Ward, have done something very rare: you’ve made me change my mind.’

‘I have?’

‘Do you know how many people have tried to make me change my mind? Grown men have given up in tears, professors have taken up holy orders, judges have become hermits.’

‘I realise that you’re strong-minded.’

‘My mind has had plenty of exercise. Of course it’s strong.’

‘But it’s also flexible.’

‘True. I see your point. I’m not sure where it gets us, but I see your point.’

‘Most people are different from ourselves,’ he said, ‘so difference actually makes us all the same, if you see what I mean.’

‘Now you’re just being confusing.’ She lifted her forefinger and tapped it up and down on her arm. ‘But if you’re saying that these Neanderthals are just as human as anyone else, I might agree. It’s just that anyone else, in this case, is a dangerous maniac.’

‘That’s fair. I’m not saying that they’re likely to be saints, no more than we are.’

‘Speak for yourself.’

‘I beg your pardon. I mean to say that I’d still like to know how they think.’

‘So that you can see how mass murder can be justified? No need to ask the Neanderthals. Look at history. The Crusades. Genghis Khan. The Inquisition.’

‘Now it’s your turn to be correct: it’s easy to find justification for mass murder, as long as you’re convinced you’re right.’ Kingsley put his chin in his hand. ‘Say what you like. I want to stop these Neanderthals, but I can’t bring myself to hate them.’

She paused and studied him again. ‘As a project, Kingsley Ward, you are by far my most interesting.’ Evadne reached behind her. ‘Would you like something to eat? We have fruit, bread, cheese.’

‘They’ve provided food for their prisoners? How very human.’

Later that day, when the six burly Neanderthals came to the cell door, Kingsley briefly amused himself by wondering if there was any other type.

It’d do me good to see a lanky Neanderthal with pipe cleaner arms.

One of the six was the black-bearded leader of the team who had pursued them across seventeenth-century London. Without a word they were marched to a room near the main workshop. Of course, this made it somewhat near the workshop that held the time machine, but Kingsley accepted that this was a moot point, guarded as they were.

The room wasn’t luxurious. Kingsley was puzzled by the manner in which everything was curved, even the pillars that held up the roof. The walls were painted with murals, scenes of forests and deserts, acutely realistic in detail, as if one could take a step and be there.

A single old female Neanderthal that Kingsley recognised as the one who had saved him from the Spawn – then set out in pursuit of him – put down a saw she’d been sharpening and hung it on a rack over the crowded workbench. She wiped her hands on the sides of her overalls. Kingsley saw her age in the way she limped – one hip was troubling her, even though she tried to hide it. Her forearms were still muscular, however, and her eyes were clear. She looked as old as the mountains.

She studied him for a moment, in the slightly distant way a farmer would look at stock. She barely glanced at Evadne, who managed an ‘I demand –’ before one of the Neanderthals clamped a hand over her mouth. She resisted furiously but her captor was impassive.

‘Is this him, Rolf?’ the old woman said to blackbeard, ignoring Evadne’s performance. Her voice was like a barrel filled with stones.

Blackbeard – Rolf – looked sideways at Kingsley with a mixture of disgust and anger, and Kingsley wondered if he’d been friendly with the Neanderthal who had vanished into the Immortals’ Temporal Manipulator. ‘Looks like him. The girl did have the phlogiston.’

‘You had trouble?’

Rolf smiled. ‘We ran into those sorcerers. Immortals. We couldn’t resist the chance to do them some harm.’

‘Harm in the past? Good. They are back in their lair now, which is bad.’

‘What?’ Rolf’s eyes were wide. ‘We tore them apart.’ He looked puzzled. ‘Here, I mean. Not back then. ’

‘Magic,’ the old woman said sourly.

Kingsley felt as if he’d been hit with a brick. The Immortals? Alive? He’d thought his brain was safe from the Immortals seeing as they’d been torn to pieces, but now?

Evadne went rigid for an instant, then shook in a frantic effort to free herself. It was futile.

The old woman lapsed into silence. Kingsley went to speak, but she gestured and one of the guards clapped a hand over his mouth as well. Kingsley didn’t struggle. He was too busy trying to read her broad face.

‘Attend to me, young Invaders,’ she said. She didn’t look at them, which made Kingsley nervous. Her gaze was slightly over his shoulder, but he knew she wasn’t talking to the row of Neanderthal bravoes behind him. ‘Your fate has been determined. Make your peace.’

Kingsley struggled then, but was held tight by two pairs of hands either side. He jerked and managed to get in a good elbow jab, but it was like hitting a slab of well-seasoned timber.

‘We have heard from the Immortals. They will leave us alone if we trade you to them,’ the old woman said. Then as she turned away, she added in a mutter: ‘The old man will break soon. I don’t need you any more.’

Kingsley shook off the muffling hand and howled as fear and shock set his wild self free.

Panting and aching after regaining control, Kingsley remained impassive while they chained him up to take him to the Immortals, but inside he raged. The beasts! Torturing an old man! He wanted to rend the nearest savage apart.

But they had learned. This time, they used manacles, shackles and chains on Kingsley instead of ropes. They were of excellent manufacture, with every appearance of being bespoke. The linkages on the leg-irons, for instance, were significantly different from those on the manacles, while the finishing showed signs of hand polishing.

They wouldn’t be a problem, he decided, even if they were heavy enough to lead a rhinoceros on a walk. Just strike the manacles on a hard surface, preferably a corner, right there where the hasp entered, and he’d be free soon enough.

They had been rough with Evadne, and Kingsley vowed to make them pay for that. She had made the mistake of resisting – to no avail, given the superior strength of the Neanderthals. Her glares made no difference either. They were impervious.

While being transported, Kingsley tried to talk to his captors. Through drains, shafts, a remarkably domed concourse, an overground stretch through a lane with merchants who specialised in Egyptian antiquities, and finally into a beautifully arched red-brick conduit with spectacular quoining, Kingsley strove to treat his captors as fellows. He put aside his rage and his embarrassment at being transported in a Neanderthal-sized wheelbarrow and asked them what they wanted, how they could be helped. They ignored him. Most did so with ease, as if he were simply a noisy farm animal, but a few of the younger Neanderthals had more difficulty restraining themselves. One finally burst out with ‘Shut your filthy face, Invader!’ and advanced before one of the more senior straight-armed him with a shove to the chest that would have put a hole in a stone wall.

Evadne, unusually, had been quiet during all this but soon after they reached a red-brick confluence of three tunnels, she mouthed, ‘My turn.’

‘Phlogiston,’ she said quietly, as if to herself, and immediately she had the attention of the entire band, even though they did their best not to betray it. ‘You’ve made some gains in phlogiston extraction.’

She went on as if they had answered, even though none of them had uttered a word. ‘I thought so. The purity looked outstanding. I’ve had to triple refine to get that concentration.’

The silence of the Neanderthals was considerably strained.

‘Of course, that would mean you’d have to double-baffle the fractionating column to avoid explosions,’ she said.

A few furtive glances among their captors.

‘Ah. You’ve learned that? I could have saved you the trouble if you’d asked.’

‘We use ammonia-based refrigeration to get over the problem,’ one of the younger Neanderthals muttered. At the disgust of his fellows, he looked down, abashed.

‘Good idea,’ Evadne said, nodding as much as she could with ropes up to her chin, ‘but my approach means a more compact unit.’

‘Enough,’ growled Rolf. ‘We’re here.’

Evadne jerked. ‘I can double your extraction rate!’

‘After we hand you over, we’ll have all the phlogiston we need.’