'Questions, questions, questions ...'

'But not answers,' I say.

'And no time for them anyway,' Celia interjects.

'Let me out of here and I'll tell you,' Clay says, staring at me.

'Tell me and I won't kill you.'

'Well, you'll never know if you kill me.'

'Nathan, there's no time for this. You have to go,' Celia says.

Clay smiles at me and says, 'Better do as you're told and run along. I'm sure I'll still be here later.'

'You'll be here forever,' I reply and swing the door shut.

When this is over I want Clay swimming in truth potions. I want Bob to dig through his brain and find out everything he knows, though in honesty I'm not sure what difference it makes any more what Annalise did or didn't do. She shot my father and that's all that matters.

thumbs.

I go to the cut that leads to the Council building, Celia following close behind barking at me, 'I need you to follow my orders. When I say go, you have to go.'

'I'm going now. OK?'

Further down the corridor I see Greatorex, Adele and a couple of the other trainees arriving. Gabriel is waiting for me at the cut in a Hunter uniform.

I turn to Celia and tell her, 'I could have killed Clay. I didn't. You told me to go. I went.'

'Eventually.'

We glare at each other.

Gabriel says, 'Did I miss something?'

Celia looks at me and says, 'Nothing important.'

It was important to me. I say to Celia, 'Annalise may be a prisoner here in the Tower. Do you want me to go and look for her?'

'No. I want you to do the mission as we planned.'

'OK. I'm going to do the mission as planned. Are you ready, Gabriel?'

He says yes and I say to Celia, 'See how good I am at following orders.'

I know I haven't got time to look for Annalise and I'm fairly sure she isn't here in the Tower anyway from what Clay said, and if she is Celia will ensure she stays put.

Celia says, 'You both know what to do.' And, looking hard at me, she says firmly, 'Do it. Stay focused and we can win this.'

Gabriel's job is to wait in the Council building, disguised as a Hunter until the fighting starts, then send a text message to Celia, and the Alliance fighters will come through the cut. I know Gabriel will be the first to join the battle. I wish he'd hang back, be last and not take any risks, but there's no point in even suggesting that. The main way to keep him safe is the way to keep everyone safe: get Soul.

Gabriel changes his appearance to a crop-haired Hunter, and I recoil. He looks almost like Kieran. He says, 'I've taken the ID of one of the Hunters that were working here. Is it no good?'

'Too good, I think.' And I grasp his hand, take a breath, become invisible and slide into the cut.

The darkness of the cut lasts only a second. Then I'm thrown out into more cold darkness, stumbling to my knees on a stone floor, Gabriel pulling me up. We hardly made a sound, but we hold still, listening.

We're in a dark room but light seeps through the cracks around the door. There are voices on the other side, two of them, but then it goes silent. I think they've left but I wait ten seconds to make sure before using Mercury's pin to pick the lock. We make our way through the corridors and I quickly get my bearings.

We're in the south-west corner of the basement. The cells are to the west, but I have to go east to the stairs that come up into the main foyer. We don't see anyone until we get to the top. Then there are Hunters. Lots of them.

Gabriel pulls me back and whispers, 'You think they're here because of the meeting or because they know we're coming?'

'Does it matter?'

'At least I don't stand out so much when there's so many of them.' And I know Gabriel will try to mingle with the Hunters, find out what's happening. 'You'd better go.'

I can only hope his natural ability to fit in anywhere works even here.

I walk slowly and carefully past the Hunters, making sure I don't touch any of them, and I'm in the huge foyer of the Council building. It's not full of Hunters but there must be over twenty of them standing either side of the main door and there's a small, slim man behind an enquiries desk.

I take the stairs three at a time, and on the first-floor landing there are more Hunters again: ten of them. I carry on up, slowly now, to the top floor. There are four Hunters on the second landing and I see two more patrolling the third-and fourth-floor corridors, but the top floor is quiet and empty.

It's different to how I'd imagined it from practising in the mock-up. The wooden floor has a strip of red carpet leading down the middle but overall it's light, airy and warm. I'd imagined it to be dark and grey. I go right and to the first door, as I rehearsed in the forest. The room is furnished and doesn't appear to be in use. I work my way along the corridor, checking each room and every one is similar and similarly unused.

I hope for better luck the other way and turn back to try the corridor that heads left from the top of the stairs into the area that Celia hadn't managed to re-create in the mock-up.

I listen at the first door but there are no sounds except the hiss of phones. That hiss fills the building: there're lots of people with phones, and lots of computers and electrical equipment. I try the handle and it opens. The room beyond is a large book-lined study. There's an old leather briefcase by the side of a wooden desk and a coat thrown over the back of a leather armchair. No one is in here but there's a door to another room. I go to that and listen again. I can hear music. Classical music.

I'm fairly sure that whoever owns the coat is in the room with the music and there has to be a good chance that the owner is Wallend. But I want to get close to him without raising the alarm and I want to find out how many other people there are on this floor.

I go out and try the next door along the corridor. This opens to a smaller office, with a desk and chair, shelves and a small sofa and some personal things: papers, a laptop and a handbag. This office also has a door leading to another room, and from it I can hear the classical music again. I think this door leads to the same place as the door in Wallend's office.

I carry on with my check of the corridor, speeding up now. The next door is locked but Mercury's pin opens it easily and I find another unused office. There's one door left to check. There are no sounds coming from behind it. I use Mercury's pin and enter.

This is not an unused office.

There are three gurneys, each with a grey cloth over them, and their shape indicates that a body lies beneath each one.

I go to the first and pull the sheet back. It's a woman. Brown hair, eyes open, staring, no glints in them. Her skin is pale. She has a tattoo on her neck: W 1.0. As I pull the sheet further back, I see that her chest is open. There is no blood that has all been taken out and, as far as I can see, so has her heart. I look at her hands to see if she has similar tattoos to me. Her little finger has a single tattoo on the side of it: W 1.0.

I go to the next body. This is also a woman, black-skinned but mutilated the same way as the first.

The last body is different. It's a girl. She can't be more than eleven or twelve. She has a tattoo on her neck and finger as well, and her chest is also open.

The room itself is cold. Very cold. The walls are lined with shelves and bottles that seem to contain parts taken out of these victims. There's drawers of surgical equipment.

There is also a door to another room. I go and listen. Nothing. No music.

I try the knob and am surprised that it's not locked. I go in.

The room is vast and contains rows of metal shelves, each protected by a glass door. And on each shelf, bottles. And in each bottle ... parts of bodies. I slide a glass door back and pick one up to check. In the bottle is something fleshy and dark. I think it might be a liver. It has W 1.0 tattooed on it.

I go to the door at the far end of the room and, yes, at this door I can hear the classical music. I'm sure Wallend and his assistant are inside but there may be guards too. And I know the chances of me getting into this room without Wallend noticing something are slim, so my options are limited. I need to move quickly. But I don't want to raise the alarm if I can avoid it.

I retrace my steps to Wallend's office, making sure the doors are locked behind me. I don't want anyone to run and escape this way. Back in Wallend's office I go to the door in the far wall and listen for the music but a man's talking now, though he's not in the room; he's on the radio introducing some Beethoven.

I take hold of the doorknob, concentrate again to ensure I stay invisible, and slowly and gently open the door far enough to slip inside the room.

Beethoven starts, nice and slow. I close the door quietly.

The room is bright. Skylights line the ceiling. At the far end of the room are two figures sitting at a bench. They are bent over, working. A man and a young woman. The man has his back to me. He's narrow, thin, wearing a white lab coat, and although I can't see his head because he's bent over I know it's him: Wallend.

The woman looks towards me and the door. She must have noticed a movement. She says something to Wallend and he turns as I approach him and he looks right through me.

The room is a laboratory, full of equipment and jars and tubes and stuff that I've no idea about. I daren't use electricity in here. I take the Fairborn and see that Wallend and the girl are not bent over a desk but a body laid out on a bench. The body of a man and on his neck is a tattoo in large letters: B 1.0. His chest is cut open, his heart exposed.

I go to Wallend's assistant and neither me nor the Fairborn hesitate. Her blood flows over my hand and the assistant's body slips silently to the floor. I allow myself to become visible.

Wallend stares at me. He has a scalpel in his hand. I hold up the Fairborn and say, 'Care to try your luck?'

Wallend steps back between the tables and turns, and I go round fast to follow him and I'm on him in three strides. I grab his arm and pull hard but he squirms round behind a desk. My hand slides down to his wrist and I slam his hand on to the wooden desktop and pin it to the surface with the Fairborn. Wallend's shaking, not resisting, and I use the scalpel to fix his other hand in place. He still hasn't said a word: no scream of pain, no cry for help.

Beethoven is playing a nice tune very soothing, gentle, not that funereal stuff.

I say to Wallend, 'I have to tell you that I'll probably kill you whether you help me or not. But the longer you live the bigger the chances are that you'll carry on living. When the rest of the Alliance gets here they'll want you alive. Want to put you on trial and stuff like that.'

He doesn't say anything, just shakes.

'I really can't be bothered with all that, though. I mean, as far as I'm concerned, you're guilty of murder. Lots of it.'

Now he speaks. 'And you're not?'

'We're talking about you today. You're guilty. The question is: can you stop me from executing you?'

'Wh-what?'

'I need you to show me how the Hunters go invisible.'

He shakes his head.

I take another scalpel from the end of the bench and go to Wallend. I chop his right thumb off. Now Wallend screams.

'Painful, isn't it?' I say. 'How's your healing?'

He's shaking again, worse now. Blood running across the desktop.

'You're not good at healing. What are you good at, Wallend? Just chopping people up?'

He looks at me, terrified, then turns away and is sick on the floor.

'You ever get sick when you're cutting up other people, Wallend?'

He doesn't reply, just shakes, which I think is a no.

'So, where are the witch's bottles that you use to make the Hunters invisible? That's how you do it, isn't it? With bottles?'

He nods.

'So?' I ask. 'Or are you going to let me take the other thumb?' I smile at him.

He stares. 'They'll kill you. Slowly, if I have anything '

I take his other thumb off and he makes a strange choking cry.

'You want to move to ears and nose next?' I ask. 'Or eyes?'

'In the next room! In the next room!'

And I glance over to where he's looking, to another small metal door between the benches.

I pull the Fairborn out of Wallend's hand and then the scalpel, and push him to the door. He's weak and quivering but he goes.

'Open it.' I could use Mercury's pin but I need to see if he'll do what I say.

'I can't. My hands ...' he says, holding them out and staring as if what's happened to them is only now registering.

I open the door. Wallend begins to collapse it's definitely only hitting him now that he isn't ever going to be able to turn a doorknob again. I push him through into the next room and he crumples into a heap on the floor. And I just stand and stare.

the dome.

It's a pyramid of glass inside a glass dome.

The pyramid is made up of glass bottles, neatly piled up on the floor. There are hundreds of them. I step closer and see that in each bottle is a small piece of flesh about five centimetres across and on it is a tattoo, a circle like the Hunters have over their hearts.

I can't get too close to the pyramid because it's inside the glass dome. There's a narrow, shallow circular channel in the floor in which the dome rests.