Aisling came home Friday night full of news about a pony called Chester and some stupid instructor named Damien Middlefield. She looked astonished when her parents wouldn’t listen and spirited her away into the living room to explain that life, for once, was not a bowl of cherries. Henry waited patiently in the kitchen, ate some yoghurt, then two fudge brownies, but eventually it got so late he went to bed. The following morning he found Aisling heavily into denial.

‘He’s so big,’ she told him enthusiastically, ‘but so gentle. And he’ll try anything, real have-a-go no matter how high they set the fences. I just wanted to pack him up in my case and bring him home with me.’ She was talking about Chester, the wonder-horse. ‘Do you think Mum and Dad would let me have a pony? I mean, there’s room. Well, there would be if we got rid of the pergola. Chester might actually be for sale. And if Dad bought the field from Dr Henderson, we’d have more than enough grazing and I could – ‘

‘What did they tell you?’ Henry asked. They were alone in the house. Mum had gone shopping and Dad, despite the fact it was Saturday, had taken himself off to the office. Both had stressed they would not be back until the afternoon. Henry suspected it was a deliberate give-the-children-time-to-talk-things-over sort of thing.

‘Well, I didn’t actually ask them about Chester,’ Aisling said. ‘I mean I hinted but – ‘

‘Oh, come on, Aisling!’ Henry said tiredly. ‘We’re going to have to talk about it some time.’

‘Talk about what?’ Aisling asked.

‘What’s happening between Mum and Dad.’

‘What’s happening between Mum and Dad?’ Aisling asked brightly.

Henry felt like strangling her. ‘Did they tell you Mum’s been having an affair with Dad’s secretary?’ he asked brutally.

‘Oh, that,’ Aisling said. ‘It doesn’t mean anything. Mum’s not gay.’

‘Mum’s not gay?’ Henry echoed.

‘No,’ said Aisling sniffily. ‘How could she be? Besides, she told me last night.’

‘Mum told you she isn’t gay, but she’s having an affair with Anais Ward? Didn’t you see the tiniest little contradiction between those two statements?’

‘No,’ Aisling said. She glanced around vaguely, like somebody looking for an escape route. ‘Don’t you have to go work for that old poop Fogarty or something?’

Henry ignored it. ‘They told you they were splitting up? Dad’s going off somewhere and we’re supposed to stay here with Mum?’

‘Won’t last long,’ Aisling told him confidently.

‘What won’t?’

‘The thing about Mum and Dad living apart. Mum’s not serious -it’s just an early menopause or something. It’s not like it’s another man. She’s just at an age when women like to experiment. You’re a boy – you wouldn’t understand. It’ll blow over and then Dad will come back. They mightn’t even get as far as separating. They both said that would take ages because Dad has to find a flat. Mum could have stopped with Anais before then.’

He’d never thought of his sister as Brain of Britain, but this was dim even for her. ‘And you think Dad will just… forgive her?’

‘What’s he got to forgive? It’s not another man.’

Henry gave in. Aisling seldom made much sense and today she wasn’t making any at all. But then everybody coped with these things their own way. Aisling obviously wanted to believe everything was going to be all right, nothing was going to change. Or if it did, it wouldn’t change for long. Then she could get back to the important things in life, like persuading Dad to buy her a pony. ‘OK,’ he said.

‘OK what?’ Aisling asked suspiciously.

‘OK, it’s not happening.’ He got up and started to shrug on his jacket.

‘Where are you going?’

‘To work for that old poop Fogarty,’ Henry said.

For some reason it made her angry. ‘Maybe if you stayed home a bit more, this whole thing might never have happened!’

He stared at her, speechless for a minute. She was just back from a week at her damn Pony Club, she treated the house like a hotel and she was telling him he should stay home more? Before he could think of a suitable riposte, something bitter and hurtful, she said, ‘What do you do for that dreadful Fogarty person anyway? I mean, old man living alone, no wife. What’s somebody like that want with a young boy coming round two or three times a week? You sure it’s Mum who’s the gay one in this family, Henry?’

‘You shut up!’ Henry snapped. He took her by the arms and shook her, so her head bobbed like a rag doll. ‘You… just… shut… up about… about everything!’ But some half-buried part of him knew she wasn’t talking to him at all, wasn’t talking about him. She was just shouting aloud to drown her own fear, trying to hold someone else to blame for what was happening to their parents.

‘All right,’ she challenged. ‘What do you do?’

The thought that popped into his head – We rescue fairies – was so ridiculous he almost smiled. With a huge effort he managed to make his voice sound calm and reasonable. ‘I clean his house, sometimes his shed. He lets things slide a bit. I think he’s over eighty.’

But Aisling was in no mood for calm and reasonable. ‘That all you do?’ she asked, in his face. ‘Just cleaning?’

‘No, as a matter of fact. Not just cleaning.’

Absolute triumph took command of her features. She stood looking at him, waiting.

What the hell, Henry thought, she’s not going to believe me anyway. And there was some sort of poetic justice about telling her the truth. He tipped his head to one side and this time actually did smile. ‘As a matter of fact, we rescued a fairy. Little fellow with wings, name of Pyrgus.’ Then, before she could recover, he headed for the door.

As he closed it behind him, he heard her sudden explosive shriek. ‘You’re the fairy, Henry! You’re the bloody, bloody, bloody fairy!’

There was a few feet of tired lawn in front of Mr Fogarty’s house to match the few feet of tired lawn at the back. The grass looked grey, as if it were slightly blackened by soot. It seldom needed cutting – the soil was poor and badly drained – which suited Mr Fogarty fine since he didn’t like working at the front where anybody could see him. Henry once offered to cut it for him, but Mr Fogarty had the idea he was too young to handle a lawnmower. Weird thing was, the old boy owned an incredibly powerful lawnmower, far too big for the amount of grass he had. It was greased and oiled and wrapped in plastic towards the back of the shed.

Henry thumbed the front doorbell, then rattled the knocker. Sometimes it took Mr Fogarty as much as five minutes to answer his door, sometimes he wouldn’t answer it at all, so Henry had to go round the back and hammer on the kitchen window. But today his reaction was immediate.

‘Go away!’ called Mr Fogarty’s voice from inside. ‘Go on – push off!’

Henry bent down and pushed open the letterbox. ‘It’s me, Mr Fogarty,’ he said patiently. He straightened up and waited.

After a moment the door opened a crack. Fogarty’s rheumy old eye peered out. ‘That you, Henry?’

‘Yes, Mr Fogarty.’

Fogarty opened the door a little further and stuck his head out. He peered both ways along the street, then reached out to grab Henry and pull him inside. ‘Where the hell have you been?’ he hissed as he slammed the door. Quite unexpectedly he gave one of his rare feral smiles. ‘Got somebody I want you to meet. Come on, come on.’

Henry followed him to the living room. Like much of the rest of the house, it was full of cardboard boxes and stacks of books. You had to step carefully to get from one end to the other. Mr Fogarty had taken to sticking brown paper over the lower windowpanes to stop his neighbours looking in, so the room was always gloomy. For a moment Henry didn’t realise there was anybody in it except for Fogarty and himself. Then there was a movement to his left and a red-haired boy about his own age pushed himself out of a tattered armchair. ‘Hello, Henry,’ he said.

‘Hello…’ Henry said uncertainly. ‘Do I know you?’ The boy had cheerful, open features and a peculiar way of dressing Henry hadn’t seen before. His clothes were dark and loose, a bit like the military gear some kids liked, but the wrong cut and colour.

The boy stuck out his hand and grinned. ‘Pyrgus,’ he said. ‘I’m Pyrgus Malvae.’

Henry frowned, wondering who Pyrgus Malvae was. Then it hit him like a thunderbolt. ‘Pyrgus! It’s you! But… but…’ He looked round at Mr Fogarty who was grinning broadly as well. He looked back at Pyrgus. ‘No wings?’

Pyrgus shook his head. ‘Not any more.’

‘And you’re… big!’

‘You noticed?’

Henry took the proffered hand and shook it. The skin felt surprisingly hard and rough. He glanced over his shoulder at Mr Fogarty. ‘How did you do it?’

‘Didn’t do anything,’ Fogarty said. ‘It just wore off.’

‘Sometime in the night,’ Pyrgus said. ‘I went to sleep that little thing with wings and woke up normal.’

‘Wow!’ said Henry. He couldn’t believe the solid boy before him was the same delicate little creature that had been sitting on his shoulder a couple of days before.

Fogarty’s eyes glinted. ‘Other thing is, you have to call him Highness. That’s Prince Pyrgus you’re shaking hands with.’

‘Don’t listen to him,’ Pyrgus said.

Henry grinned now. ‘You’re not a prince?’ Pyrgus didn’t look like a prince.

Pyrgus sucked air through his teeth uncomfortably. ‘Actually, I am. My father’s the Purple Emperor. But nobody calls me anything but Pyrgus.’

‘Lot of things happened since you skived off home,’ Fogarty said sourly. ‘Pyrgus says Faeries of the Night must be behind the UFO abductions.’

Henry blinked. ‘Wait a minute – how did we get to UFO abductions?’ And what are Faeries of the Night?

Pyrgus said, ‘Mr Fogarty has been telling me about how your people are getting kidnapped by small beings with large eyes and thin limbs. Faeries of the Night use creatures like that – in my world we call them demons.’

Demons, Henry thought. Pyrgus was as big a nutter as Mr Fogarty. Carefully he said, ‘And Faeries of the Night are what?’

‘Bit hard to explain,’ Pyrgus said. ‘They’re sort of different from Faeries of the Light.’

Henry started to feel like he was drowning. ‘What are Faeries of the Light?’

‘My lot,’ Pyrgus told him cheerfully.

‘So you see why it’s important you’re here,’ Fogarty said to Henry.

‘No,’ Henry said.

‘So we can send Pyrgus back,’ Fogarty told him patiently. ‘We were going to help him for his own sake, of course, but now there’s another reason, isn’t there? He gets back to his own world, he can get his old man to close down the portals the demons use. Stop the whole abduction business.’

‘I see,’ Henry said. Portals. Fairies. UFO abductions. Demons. He glanced at the brown paper stuck to the windows. He supposed it wasn’t all that much more of a lunatic asylum than the one he’d just left. ‘It’s important I’m here so we can send Pyrgus back.’

‘Good,’ said Fogarty impatiently. ‘Now let me show you how we’re going to do that.’

As they followed Fogarty towards the kitchen, Henry whispered to Pyrgus, ‘There’s no such thing as flying saucers.’

Still frowning, Pyrgus said, ‘But Mr Fogarty told me six million Americans were abducted last year. Americans are people – right?’

‘Yes. Yes they are. But it didn’t happen. Mr Fogarty just thinks it happened.’

‘Why does he think that?’ Pyrgus asked, bewildered.

Because he’s barking mad, thought Henry.

‘What are you two whispering about?’ Fogarty asked suspiciously. He hated people whispering.

‘Nothing, Mr Fogarty,’ Henry said.

There was an enormous blueprint on the kitchen table. It showed a piece of machinery like nothing Henry had ever seen before. Two symbols were marked ‘tesla coils’ and seemed to be electrical, something borne out by what looked like a drawing of a power pack. But there was conventional machinery as well, the sort of cogs, levers and wheels you might see in a Victorian flour mill. Strangest of all was a circuit diagram labelled ‘Hieronymous Machine’. A spiral antenna emerged from one end, emitting – or absorbing – a little lightning flash with ‘eloptic radiation’ written beside it in Mr Fogarty’s neat block capitals. Henry checked twice to be sure, but no part of the Hieronymous Machine was connected to the power pack. He looked up at Mr Fogarty. ‘What is it?’

‘That’s a design for the first completely artificial portal between the Analogue Worlds,’ Fogarty told him proudly.

Henry looked at Pyrgus, then back at the blueprint. Apart from the cogs and wheels, which he could follow well enough, none of it made any sense to him. ‘How does it work?’ he asked.

‘While you were podging at home,’ Fogarty said sourly, ‘Pyrgus and I were working on this. Pyrgus told me every detail he could remember about his portal and eventually I figured out the basic principle had to be the same as a Hieronymous Machine.’

‘What’s a Hieronymous Machine?’ Henry asked.

Fogarty gave him a withering glance. ‘Don’t they teach you anything at school? First one was patented by Galen Hieronymous in 1949. Little thing he lashed up to detect the metal content of alloys. Somebody sold you a gold brick, you could use the thing to tell if there really was any gold in it.’

‘Never heard of – what? Hieronymous, was it? -never heard of it,’ Henry said a little sulkily.

That’s because it didn’t catch on,’ Fogarty told him. ‘Trouble was, about one in five people couldn’t get it to work.’

‘Too complicated?’ Henry asked.

Fogarty shook his head. ‘Naw, you switched it on, put a sample near the pick-up coil, then read off the results with your fingertips on a detection plate. Easy-peasy.’

‘So what was the problem?’

‘Nobody knew,’ Fogarty said. ‘But a character called Campbell found out. He set up experiments with people who could get the machine to work. One of them was a kid not much older than you. He switched on the machine, tuned it in and tested a whole heap of samples. Worked fine. Then Campbell noticed he’d forgotten to plug it in.’

‘That’s impossible,’ Henry said. He didn’t know a lot about electronic gadgets, but he knew enough to know they didn’t work without power. An idea struck him. ‘Maybe it was picking up static electricity or something.’

‘Campbell tested for that,’ Fogarty told him. ‘Wasn’t static. Run a phase test and you’d find there was no electricity in there at all. Looked like an electronic machine, worked like an electronic machine – valve blows, they used valves in those days, and it stopped -but it wasn’t an electronic machine. Had to work some other way. Only thing that made sense. They finally figured what made it work was faith.’

After a second, Henry said, ‘You’re kidding me, aren’t you?’

Fogarty, who had no sense of humour, looked at him soberly. ‘Henry,’ he said, ‘everybody knows electronic machines work – we’re used to them, see. They always work. So make something that looks like an electronic machine – but make it properly with all the parts in place – and it works anyway. Something happens between your mind and the machine. Except for one clown in five who doesn’t have the faith.’

Henry glanced at Pyrgus. ‘Is this making sense to you?’

‘Oh yes,’ said Pyrgus seriously. ‘Wizards use that principle in my world all the time.’

Fogarty said, ‘Doesn’t matter if it makes sense – the theory’s sound. This thing will work. All we have to do is build it.’

Henry looked at the blueprint again. ‘Where are you going to get the parts?’

‘I’ve got a lot of bits and pieces here,’ Fogarty said, ‘and I know where I can buy the tesla coils. But there are one or two components for the Hieronymous circuits that could be a bit tricky if we want them in a hurry. Which we do.’

‘So where do we get them?’ Henry asked innocently.

Fogarty said, ‘You’ll have to steal them from your school.’