'Come on. Let me show you what's possible and what isn't. Let me show you what you could be, Tess. Before it's too late.'

And with that he was an owl again, lifting towards the skies. This time, Tess followed.

It was exhilarating to be up there, with eyes that pierced the darkness and wings as silent as the watching moon. Beneath them as they flew, the woodland creatures clung to their shadows and waited for their pale enemies to pa.s.s over. Tess followed compliantly as the owl that had been Kevin spiralled higher and higher. The lights of the house became visible, and so did the dejected figure of Uncle Maurice, crossing the fields yet again on his way to search for the children.

Higher still the two birds rose, until they were above the level of the crag and looking down on to its plateau-like summit, where the moonlight threw shadows from heaps and jumbles and circles of stone which were almost as ancient as the mountain itself. Beyond that the grey, fluid shapes of the Burren range stretched away to the edges of vision.

Tess was so entranced by the surroundings that she missed the exact moment when the other owl began to drop down out of the skies again. She followed at a distance, and he waited for her, swooping up again, then falling past her, almost drawing her into his wake. This time she kept up, reminded of another time, long ago, when she had followed Kevin in an electrifying dive into a building in Dublin. He had been a different kind of owl on that occasion and both of them had been different people. It seemed like an eternity had pa.s.sed since then.

Faster and faster they fell until the thick canopy of the trees was racing up to meet them. Without hesitating, the other owl plunged straight through the leaves and, holding her breath, Tess followed. What came next happened in the blink of an eye, but there was somehow time for a thousand thoughts to flash through Tess's mind.

They entered the woods close to the crag, and the instant that Kevin was beneath the trees he levelled up and flew at breakneck speed straight towards the rock. A shock-wave pa.s.sed through Tess's body, and at the same time she began to flap madly, trying to slow down and change direction at the same time. It seemed that Kevin was certain to be killed, but he wasn't. If Tess hadn't seen it with her own eyes, she would never have believed it.

Without slowing, without changing direction, he continued to fly straight towards the rock-face. But just when the bone-crunching collision seemed inevitable, he vanished. There was no doubt at all about what had happened. The owl that was Kevin hadn't Switched, nor had it become invisible. It had simply flown straight through the solid face of the rock.

CHAPTER SIXTEEN.

DESPITE HER BEST EFFORTS, Tess couldn't reduce speed fast enough. Her left wing glanced against the rock and she tumbled down the last few feet of its face like a fluttering Catherine wheel. At the bottom she picked herself up and shook her feathers, then Switched into her human frame.

Her left arm was sore and she knew by the feel of her hips and shoulders that she would have a few bruises tomorrow to show for that fall. But on what kind of body she still couldn't imagine. Tomorrow was a blank in her mental map.

And today was a disaster. She slumped to the ground and sat with her back against the rock, ignoring the damp which was beginning to soak from the mossy ground into her jeans. She found that she was no longer afraid, but she was angry. Angry at Kevin for playing tricks on her. Angry at Lizzie for talking in riddles. Angry at herself for failing to gain entrance to the rock. Even as the thought came to her, she understood why it was that she had failed. There had been an instant, she remembered, immediately, after the other owl's disappearance, when she could have followed it. In that instant she had known that the key to the door in the rock was not a thing that she could find or touch, nor was it a puzzle that she could work out with her mind. The only things that could get her through were faith and courage; the ability to let go and allow herself to be governed by another reality; one that she did not understand. In that brief moment she had known all that, and she had chickened out. That was why she was still there, all alone on the outside; the one who had failed. The one left behind.

Lizzie's words returned to her again. What did she mean by believing what we see or seeing what we believe? She was certain that the words had some bearing on her situation, but she didn't know exactly how. Tess stood up and looked at the rock, but she knew in her heart that it was already too late. She had missed the moment of truth and she couldn't recreate it. She could hear her uncle's arrival at the edge of the woods; the snap of a broken branch, a whispered call.

Tess no longer knew what to believe. Somehow she had entered another world, where things weren't as they seemed, and where the rules she had come to have faith in didn't seem to apply. She wanted to believe in it. She just didn't know how.

But someone else did. The touch on her ankle was so soft that she thought a moth had brushed her and she leant down to scratch the itch. But it wasn't a moth.

'Tail Short Seven Toes sad, huh? Huh?'

Cat Friend was standing on her hind legs, clutching on to Tess's jeans with her front paw.

Tess couldn't help smiling despite her dejected mood. 'Yup, yup,' she said. 'Tail Short Seven Toes trying to get into the rock. Left all alone and sad.'

'Cat Friend helping,' said the little rat. 'Cat Friend leading Tail Short Seven Toes into the rock.'

The images were perfectly clear and Tess's spirits soared. She knew that it could work. There was no doubt at all about Cat Friend's belief and Tess felt sure that it could bolster her own sufficiently to cross the subtle barrier. But they would have to be quick. From among the trees came the sound of a grunt and a mild curse as Uncle Maurice lost his footing. He was almost there.

Tess Switched into rat form and, although Cat Friend jumped at the abruptness of the change, she didn't falter. A moment later they were scurrying towards the rock. At Cat Friend's suggestion, Tess took hold of her tail and closed her eyes. And as they began to move forward, she called on all the courage that she had ever had.

It seemed to take forever to get there. Tess waited for a resistance of some kind, or a shift in the atmosphere like the one that she experienced every time she Switched. But it didn't happen, and after a while Tess began to think that Cat Friend must be making a fool of her. But when she opened her eyes she was amazed to find that she was inside the hill and, judging by the distance they had covered, had been for some time.

She let go of Cat Friend's tail and stopped to look around. They were in a long, dimly-lit hall like a broad tunnel, lined with rough stones from the base of the walls to the crude arch high above their heads. To a rat the place was enormous, but Tess guessed that the roof would not have been much higher than a man's head. She wondered vaguely who would have built such a place, but more perplexing was that still there was no sign of Kevin or the children.

Cat Friend seemed equally perplexed, and the two rats conferred briefly before moving on across the stony floor. At the end of the hall a stone wall blocked their way, but on the left, low down, was a hole in the wall. Although it was huge for a rat, it was small for a human. A child might have crawled through, but an adult would have had to lie down on their belly to squeeze in. Since there was no other way forward, the rats went in, all their senses straining for any signs of danger.

Before they had gone more than a few feet along this smaller tunnel, they heard sounds of life ahead, and their way was lit by a strange, golden light. A moment later they emerged into a second hall. It was roughly the same size and shape as the one they had just come through, but there all similarity ended.

For this hall was, without doubt, a fairy sidhe. The mysterious light that they had encountered flooded the enclosed s.p.a.ce, but there were no lamps nor was there any opening to the outside. Tess and Cat Friend crouched at the end of the small tunnel, trying to get their bearings in the extraordinary surroundings.

The first thing Tess noticed was Orla and Brian, who were standing nearby and were involved in what appeared to be a rather cruel game. They had a small, black kitten, and they were tossing it between them as though it was a ball. Beyond them was a table, covered with the most scrumptious food that Tess had ever seen and, further on still, she could see Kevin sitting on a pile of silken cushions, looking sulky.

Tess touched noses with Cat Friend and was about to move forward when she felt a large hand grasp her tail and lift her from the ground. Quicker than thought, she twisted in the air, in an attempt to bite the aggressor, but before her teeth reached their target the hand jerked away and she found herself being flung through the air in a wide arc.

Before she began to descend she Switched into a bat and flew on up towards the ceiling, where she gripped a rough edge of stone with her paws and waited to get her bearings. Beneath her the game had abruptly ended and Orla was clutching the kitten, which clung to her jumper with tiny claws. Beyond them Kevin was on his feet, and they were all staring towards a boy who stood beside the crawl-hole.

He, in turn, was gazing up at her. He appeared to be a teenager, around her own age. His eyes were grey and he had fair hair, but beyond that it was hard to describe him in terms of the human race. He was dressed in clothes that glimmered and moved like molten silver and gold, and his skin shone with the same, golden light that suffused the sidhe so that it was difficult to say whether he reflected the light or created it. But despite his extraordinary appearance, there was something about his face that was familiar to Tess. She was still racking her brains, trying to work out what it was, when he began to speak.

To her bat-brain the sound was meaningless; a booming resonance bouncing around the confined s.p.a.ce. Intrigued, she dropped from the ceiling and fluttered to the floor beside the table, where she Switched into human form.

'Yay! Here's Tess!' Orla shouted.

'Yahoo!' yelled Brian. 'What took you so long, eh?'

Orla tossed the little black kitten towards her. As she caught it, it transformed itself into Colm, red wellies and all. Tess was so surprised by the sudden change in weight that she dropped him, but he changed into a huge, brightly-coloured b.u.t.terfly as he fell, and went fluttering off around the hall.

Tess laughed, delightedly. It was like a dream come true, being among friends, all Switchers, with no one to keep secrets from And when she perused the loaded table, she knew that she was really in heaven. All her favourite foods were there; macaroni cheese and sausages and heaps of chips with vinegar and tomato ketchup, and trifles and cream buns and too many things to take in. She reached for a chip and was about to put it in her mouth when Kevin roared from the other end of the hall.

'No, Tess! Don't eat it!'

She turned and stared at him, dumbstruck. He ran over.

'Don't eat it, Tess,' he said again. 'Don't eat anything, you hear? Nothing at all.'

From the opposite end of the hall, the strange boy advanced, speaking as he came.

'Don't listen to him, Tess. He has some very strange ideas. I can't imagine where he got them from.'

The boy was so handsome and had such an ethereal quality that Tess found it hard to disbelieve him.

'Take some, go on. Help yourself.'

But Kevin was determined. 'No, Tess. Please listen. You know it yourself, if only you'll stop and think.'

'Think about what?' asked Tess, her irritation growing. She was remembering Kevin's deceitfulness earlier, and was not inclined to give him the benefit of the doubt. But her dilemma was shelved for the time being by a new turn of events.

Brian stepped forward and, as proud as punch, stood between Tess and the radiant boy.

'In any case,' he said, 'we are forgetting ourselves. I think we all know who you are, Tess. But I don't think you have met our Uncle Declan.'

CHAPTER SEVENTEEN.

TESS TOOK SEVERAL STEPS backwards, not because there was anything threatening about Declan's manner, but because she was afraid that if she took the offered hand it might not feel like flesh. Kevin moved over to her, protectively she thought, but it didn't stop the blood draining from her face, and for a moment or two she was light-headed and faint.

Declan smiled at her reaction.

'What's wrong?' he said. 'You look as if you've seen a ghost.'

'And haven't I?' said Tess.

He laughed. 'I can understand why you should think that,' he said.

The b.u.t.terfly came flitting over and landed on Tess's shoulder. This time she was ready for the change, and she hefted Colm down on to her hip as he Switched.

'Go home, Tess?' he asked.

'Of course we will, Colm. I'll bring you home soon.'

But Kevin shook his head. 'You can't, Tess,' he said. 'He won't let them.'

'How can he stop them?' she said. 'Will somebody please explain to me what's going on?'

Colm wriggled to the ground and headed towards the table.

'Don't eat anything, now,' said Orla.

'Wanna sausage,' said Colm, reaching for one.

'Why can't he have one?' asked Tess.

'Because he'll have to stay here for ever if he eats anything,' said Brian.

'He's right,' said Kevin. 'Don't you remember the rules?'

'What rules? The rules of what?'

'Of places like this,' said Kevin. 'About not eating the food, no matter how delicious it looks.'

Orla had succeeded in prising the sausage out of Colm's hand, and was standing between him and the table, warding off the well-aimed blows that he was raining upon her.

'But that's ridiculous,' said Tess. 'That's just stuff out of fairy stories.'

Her words met with silence, and as she looked around the hall, she discovered that every eye in the place was turned to her, as though she was an idiot; the last one to get some glaringly obvious joke.

'It's ridiculous!' she said. 'You can't be for real.'

Still everyone stared, until she went on. 'This is the twentieth century, for cripe's sake! You're not trying to tell me there's such a thing as fairies!'

The silence that met her words was her answer. She shook her head incredulously.

'Where are they, then? These fairies?'

All the others turned their eyes towards Declan.

'But he's not a fairy!' said Tess. 'Fairies are little people who flit around in the woods and play tricks on ...' She stopped, remembering some of her recent experiences. '... and they're small,' she finished, lamely.

Declan laughed; a clear, birdlike sound that echoed throughout the long chamber.

'They're small except for the big ones,' he said.

'And they're big except for the green ones,' said Orla.

'And they're green except for the pink ones,' said Brian. 'And they all have wings except for the ones without them!'

The hall rang with laughter, and Tess would have felt left out; like a new girl at school all over again, if it hadn't been for Kevin. He wasn't laughing, and he took another protective step towards her.

But she hadn't forgotten his deceit. 'I don't know how you can be so stuck on the rules anyway,' she said, glaring at him. 'Since you seem to be able to break them when it suits you.'

'What rules?' said Kevin. 'What rule did I break?'

'Only the one that says you can't Switch any more after you're fifteen!'

Kevin shook his head in bewilderment. Colm came back and slipped a sweaty hand into hers.

'Go home, now?' he asked.

'Soon, Colm. Soon.'

She turned back to the others, and as she did so the blood left her brain again and she had to lean against the wall for support.

For there were two Kevins, identical in all respects.

The one beside her, the real Kevin, went pale and turned away. The other one laughed, and, just for an instant, the shadow that he cast upon the wall behind him grew about three feet taller and sprouted antlers. Tess took a step back, but before she could take any more drastic action the looming figure shrank and the second Kevin became Declan again.

For a long moment, everyone was too stunned to speak. But eventually Kevin found his voice. 'So that explains it,' he said. 'That's how you saw me in the woods. Except that it wasn't me at all. It was him.'

'But which one was him?' said Tess.

'The one who took the kids,' said Kevin. 'The other one was me. The one on the bicycle.'

'So how did you get in here?' Tess asked.