'Well. You know where he'll be sleeping during the day, don't you? We'll just have to dig our way in there and do the old stake through the heart job.'

He spoke as if it were an everyday occurrence, like swatting a wasp with a newspaper. But the prospect filled Tess with horror.

'I hope we find him first,' she said. 'I prefer diplomatic solutions on the whole.'

It was nearly midnight when they reached Martin's house in Phibsboro. There were no lights on, but Tess took a chance and knocked on the door. As they waited, the rain worsened and blew against them, soaking into their hair and dripping down their necks. Tess wriggled with discomfort but Kevin didn't seem to notice, partly because he was still overawed at being human again. He gazed round at the dull houses as though he was in Disneyland. Tess sighed and knocked again.

'It's no good,' she said. 'If he's in, he's not answering. Wait here, will you?'

She was on the point of Switching into a rat when she remembered the compelling power that the vampire still held over all the rats' minds in the city. On impulse she tried a mouse instead, and found immediate entry into the house by way of a missing chip of concrete underneath the front door.

The hall was vast to her tiny eyes, stretching upwards and outwards into a dark oblivion. It was full of smells, alive with them; some appealing, others threatening. Mouse life was about weighing up the balance of the scents in the air all around. If danger weighed too heavily, then a change of plan was required. If it didn't, a chance was worth taking. But at that moment, it was all too much for Tess's already exhausted mind, so she Switched into a cat instead and padded swiftly and silently up the carpeted staircase. Outside Martin's room she Switched back to human shape again and, with her heart in her mouth, pushed open the door.

Inside it was too dark to see anything. The video clock, still mindlessly flashing, distracted her attention and left dizzying green patches on her retinas. She held out a hand to block it from view.

'Martin?'

If he had got home, he couldn't have been there for long; certainly not long enough to get to sleep. She listened carefully, but there was no sound of breathing. Her skin crawled as she suddenly imagined the vampire there beside her, leaning across in the darkness ...

With a hand that trembled slightly, she felt around behind the door frame until she found the light switch and flicked it down. The bare bulb blinded her for a moment, but even as she squinted and blinked she could see that the room was empty. The bedclothes were crumpled and the floor beside the bed was cluttered with the familiar collection of socks and tea cups and video cases. Everything was as usual, except for Martin. Tess swore to herself in a whisper. Because if he wasn't there, where was he?

She turned out the light, became a cat again, and was just about to go back down the stairs when her sharp eyes noticed another door along the landing which stood ajar. The black hair along her spine stood up as she remembered Martin's anaemic mother. If he was taking a late-night snack she would rather not know about it. But she had to. If there was any chance at all of getting to him before dawn, she had to take it.

Martin's mother was alone in the room, sleeping on her back in a battered old double bed that she must once have shared with her husband. Her face was deathly white in the dim light which entered from the street and for a moment Tess feared the worst. But as she slipped across the floor, her paws making no sound on the nylon carpet, Tess's sensitive ears picked up the faint rise and fall of shallow breath. She was alive, but undoubtedly weak. The implications were obvious. If Martin remained human, she would recover; her anaemia pa.s.sing away as mysteriously as it had come. But if he chose to live out his existence as a vampire, then one more feed could finish her off and she would become like him: the first of many.

Would she take that other stone coffin, the one that Martin had reserved for Tess? Would Tess and Kevin have to bring two stakes down into the crypt with them, to be sure of finishing the job?

The black cat turned and bounded down the stairs, becoming a mouse between the bottom step and the floor and tumbling along the ground a few times as it slowed down. It flowed like toothpaste under the door and disappeared beneath the foot of a girl who hadn't been there a moment before. Luckily there was no one there to see the first part, and the only person who saw the girl appear was not surprised at all.

'Well?' he said.

'Not there.'

He sighed. 'Looks bad, doesn't it?'

'Maybe. Maybe he just needs time on his own to try and come to terms with things.'

Kevin looked around as though he hoped to see beyond the buildings into the darkness. Out there somewhere was either a boy coping with a private grief or a being on the point of entering perpetual night.

Tess shivered. Kevin slipped out of his parka and hung it over her bony shoulders.

'Your turn,' he said, before she could object.

It was heavy with rain, but still warm. Tess glanced up and down the street, hoping against hope to see Martin strolling down the pavement towards them. But from one end of the street to the other, nothing moved.

'I suppose there's no point in standing here,' she said. 'We might as well go home.'

CHAPTER TWENTY.

IT WAS WELL INTO the early hours of the morning by the time Tess and Kevin got home to her house on the edge of the park. Kevin shivered as he waited for Tess to turn the key in the lock. She looked at him and shrugged, abandoning them both to whatever trouble lay in store for them, then pushed the door open.

Immediately there was a noise from the direction of the living room: the flutter and slap of a newspaper being hastily thrown aside. A moment later Tess's father appeared in the hall, his face taut with worry which was rapidly turning to anger. He stopped dead in the middle of the hallway when he saw Tess's companion and an awkward silence hung on the air as she closed the front door behind them and slipped out of Kevin's jacket.

'Dad, this is a friend of mine, Kevin.'

Her father nodded, wrong-footed, uncertain whether the occasion called for civility or righteous indignation. Before he could make up his mind, his wife appeared at the head of the stairs in her dressing-gown.

'Oh, there you are, Tess. Where on earth have you been?'

Tess hung the sodden jacket on a spare hook inside the door. 'It's a long story, I'm afraid.'

'You're not getting out of it that easy,' said her father. 'I don't care how long the story is, I want to hear it.'

Tess's mind threatened to go on strike. The best she could dredge up was the same excuse she had given them in the park earlier that day.

'We had to go and call on that sick friend. The one I was telling you about.'

'Oh, I see.' Her father's tone betrayed his scepticism. 'The sick friend again. And you were there until one-thirty in the morning, were you?'

'Not exactly. But we ran into a few difficulties.'

'Clearly. And for some reason you decided to bring one of them home with you.'

'Seamus!' said Tess's mother reproachfully. 'Don't talk about Tess's friends like that. Not without giving them a chance, at least.'

'Right,' said Tess, looking cryptically at Kevin. She needed help, but from the look of him she was unlikely to get it. He was standing with his hands in his pockets, dripping on to the hall carpet and looking self-conscious. Tess felt sure he was going to get sulky and clam up, the way he had with Lizzie, but to her surprise he pushed his wet hair out of his eyes and said, 'The phoenix escaped from the zoo. We met the zoo-keepers searching for it.'

'Yes,' said Tess. 'I saw it escape and I followed it.'

'Then she slipped on a frisbee and knocked the stuffing out of herself.'

'Oh, Tess. Did you?'

'Yes. But I'm OK, honestly. It just delayed us a bit. And now it's too late for Kevin to get home. So can he stay the night?'

Tess's father looked from one to the other, suspiciously.

'Is all this really true? It sounds very unlikely.'

'It's true. Every word of it,' said Tess.

'And what about your sick friend? Where does he fit in?'

Tess felt sick herself at being reminded of Martin. He could be out there in the night, feeding on some poor innocent's blood, preparing to return to his new underground bedroom. She glanced at Kevin as she said, 'We missed him in the end. We'll have to try again tomorrow.'

Tess's mother came down the stairs, the long hem of her dressing-gown covering her bare feet. She stood in front of Kevin and looked closely at him, as though trying to see into his soul. Then she said, 'Does your mother know where you are?'

'No,' said Kevin, looking her straight in the eye. 'But then, she never does. She doesn't take any interest, really. She certainly won't be worried about me.'

'Are you sure?'

'Positive.'

She examined him for a few seconds longer, then sighed. 'Well, whatever else you do, you'd better get out of those wet clothes before you catch pneumonia. Do either of you want a bath?'

Tess shook her head, but Kevin nodded eagerly. 'Yes, please. I can't remember the last time I had a bath!'

Tess cringed and her father looked astonished, but her mother laughed and gestured to Kevin to follow her up the stairs. She exchanged a complicitous smile with Tess over the bannisters which made her heart swell with pleasure. At least she had one ally in the house.

When she had towelled herself down and put on dry clothes, Tess sorted out a genderless tracksuit and left it outside the bathroom door. Then she went to help her mother, who was making up the bed in the spare room for Kevin.

'What about this sick friend of yours?' she said. 'You're being very mysterious about him.'

'Oh, there's nothing so mysterious, really.' As she spoke, Tess realised that despite their conspiratorial understanding of a few minutes before, they could never understand each other about some things. 'He's under a lot of stress,' she went on. 'His father died in an accident and he hasn't really got over the shock of it yet. He needs a lot of support.'

'You should have told me before,' said her mother. 'I'm all in favour of you being helpful like that. Perhaps I could help, too? Bake a cake or something? Would he like that?'

Tess fought back the deluge of ironic laughter that threatened to swamp her faculties. She pictured her mother walking into the vampire's lair, entirely unsuspecting, holding out a perfect specimen of her famous Lemon Drizzle.

'He might,' she said. 'We'll have to wait and see how things turn out.'

They finished making the bed, then her mother turned on the electric blanket and went back to her own room. On her way downstairs, Tess met her father coming up with two cups of cocoa.

'Oh, thanks, Dad.'

'For what? These are for your mother and I. It's late enough as it is, and I'm supposed to be at the office early in the morning.'

'Oh.'

'There's plenty of milk in the fridge if you and your boyfriend want to make some.'

'He's not my boyfriend!'

'Good.' Her father's face softened and he moved both slopping mugs into one hand and reached out with the other to muss up Tess's damp hair. 'But whoever he is, don't be staying up all night, you hear? I don't know about him, but you have to be on the school bus at half past eight.'

School past, school future; both of them seemed light years away. But she nodded at her father and made a show of looking at her watch.

'Don't worry, Dad. We won't be up much longer.'

'Goodnight, then.'

'Goodnight.'

Tess had made cocoa and a pile of sandwiches before Kevin eventually finished soaking in the bath and came down. He was a fresh, pink colour, and his hands and feet were wrinkled like prunes. Together they raided the cupboards for crisps, biscuits and fruit, then they brought the whole feast up to Tess's bedroom.

'You've redecorated,' said Kevin, looking around him.

'Last year.' Tess put down the tray and slotted an R.E.M. tape into the ca.s.sette deck. 'My dad wanted to cheer me up.'

'Cheer you up? Why?'

Tess blushed and turned away, not wanting to tell Kevin how upset she had been when she thought he was dead, and how strongly it had affected her life. The music began with a boom, and she grabbed for the volume control before it could wake her parents.

Kevin started into the sandwiches. Tess had made one with apricots and cashew nuts and put it on the top of the pile, and for a long time neither of them could do anything except laugh. When they finally recovered themselves, Kevin said, 'It's so good to be human again. You have no idea, Tess.'

'Really?' she said. 'I thought it was wonderful, being a phoenix.'

'It was, for a while. But it's like, what do you do once you're perfect? Nothing to be afraid of, nothing to strive for. Hardly living at all, really, is it?'

Tess shrugged. 'If you say so,' she said. 'But I'm still not sure how it happened, how you came to Switch back even though you're over fifteen.'

'I didn't get it to begin with, either, but I think I do, now. I think that I could only exist as a phoenix as long as Martin existed as a vampire. We counterbalanced each other in some way.

'That's right,' said Tess. 'Lizzie said something like that. I just didn't understand it at the time.'

'And it was you who changed us, Tess. By deciding that you wouldn't become like either of us.'

'But how do you know I decided that?'

'I could feel it. I was part of the fight, remember?'

'Does that mean that Martin isn't a vampire, then?' said Tess.

'I don't know,' said Kevin. 'That would be the proof of the theory, I suppose, if it did. But I certainly wouldn't like to bank on it.'

They both fell silent, contemplating what he had said. Then Kevin said, 'Who lives in the cage?'

'No one.' Tess explained about Algernon and the vampire's control of the rats. As she spoke, they both became aware of the black, empty gaze of the window, and Kevin got up to draw the curtains.

'Do you think he's out there?' said Tess.

Kevin thought for a minute, and there was no sound apart from the tinny beat of music being played more quietly than it was meant to be.

'I don't know,' he said, 'but I feel as though I ought to. There should be some way of knowing, shouldn't there? Not logically, perhaps, but instinctively.'

Tess sat still, trying to work out what she felt. 'There's some kind of danger out there in the dark,' she said.

'I know that. But there always has been, hasn't there? And there always will be-places where it's not safe to be. Trouble is, it's like traffic accidents; you never know until it's too late.'

The mention of accidents reminded Tess of what she and Martin had been talking about. 'The crazy thing is, I don't blame him for what he did. I mean, shutting himself off like that and becoming cold and mean.'