Gabriel takes my hands and interlocks his fingers with mine. 'But then it will be over. No more boredom, no more terror, just lots of peace and climbing and coffee and croissants.'

'Yeah.' But I'm not thinking of peace or climbing or coffee, I'm thinking of hours of terror and all the blood and screams and fear.

It's getting light now. A delivery van comes and drops off newspapers on the street and then the newsagent opens up. Gabriel goes to buy some snack bars. I can hardly swallow them but I force them down. Then there's more waiting.

Celia appears round one of the towers. It's 7:29 and I have to go.

Gabriel says, 'I'll join you soon.'

I jog across the expanse of open ground to the Tower, through the broken door, up the smelly staircase, past the sick on the seventh-floor landing and already I feel good. The tension in my stomach has gone. I'm dying to get on with it.

I go invisible and carry on up the stairs to the top floor and the door to the prison. I've got one of Mercury's hairpins that magically picks locks and, leaning close to the door, I say quietly, 'Throttle back,' as I put the tip of the hairpin on the lock and push.

Nothing happens.

My throat is dry and maybe my voice was unclear. Or maybe the password is wrong, but I can't go through lots of options.

I can hear footsteps on the stairs. The guards aren't due to change over for twenty-five minutes so it's probably another resident. But still I need to get through the door. I say 'Throttle back' again, a little louder and clearer, but it seems like a shout in the quietness of the building. I put the pin on the lock, push the door, and it opens.

Now I'm standing in the dark. I got a quick glimpse of the next door two or three paces in front of me. But there's no handle on it and I don't know which way it opens, so I can't tell which side of the room I should be on to slide in with the guard. I'm not sure if there's a light in here but I daren't look for one and put it on. I've just got to hope that when the guard arrives I have time to get into a good position. It'll be another twenty minutes or so.

But a minute later the outer door opens. It must have been a guard on the stairs. I have a second to go invisible and the guard pulls a cord that hangs from the ceiling, illuminating a bare bulb, and the outer door swings shut. He knocks on the inner door five times. Two loud and slow and three fast, which I guess is another signal.

After nearly a minute, the peephole in the inner door slides across for the briefest of seconds and then back into place. The lock rattles and then the door opens and the guard on the inside says, 'Early for once.' He lets the door swing open for my guard to enter. There isn't much room for me, but I slide to the side and hold myself tight against the wall.

I'm in.

The returning guard swears and looks down. A sweet wrapper is stuck to his boot. As he bends forward to pull it off, I shrink further back against the wall. His jacket touches mine. That's all, nothing more. But somehow I know he knows there's something wrong. And he turns round as if to check behind him, staring straight through me, with the sweet wrapper between his fingers. He turns away again and says, 'Is Jake here?'

'You're the first. You're half an hour early. Dale's still finishing his rounds.'

'I thought I heard Jake ...' Then he wanders up the corridor, the sweet wrapper held out in front of him. And I have a bad feeling he's working it out.

I follow the sweet-wrapper guy through to a small room with a set of kitchen units along one side and a table with a bench seat along the other. He puts the wrapper in the bin then wipes his hand on his trousers. He takes his jacket off and hangs it on a hook on the wall. The other hooks are full. Another guard comes in and says, 'You're early.'

'Yeah.'

'She throw you out or something?'

The sweet-wrapper guy shakes his head, as if he has other things on his mind. He fills the kettle and makes a tea. Then more of the leaving guards arrive and comment on the sweet-wrapper guard's early arrival. Even I'm getting fed up with their comments now but it seems he's forgotten about hearing me say the password. The room fills up with more of the new shift arriving and I move into the corridor and wait out of the way and concentrate again on staying invisible. I count the old guards out as they leave and I make sure all six go. I then follow the Hunters as they leave too, and see where the cut is that they go through to the Council building.

So now there are four Hunters and six Council guards here. And I've got to remove them without letting any escape or raise the alarm. They all go to a meeting room and the lead guard is giving instructions, comments about prisoners. The guards don't carry guns: they don't need weapons as they don't let the prisoners out. They're just a food-dispensing and waste-disposal system. The Hunters do have weapons, of course.

Luck is now on my side, though. The Hunters are standing together at the side of the room. I'm standing in the doorway. The lead guard is talking about the cleaning rota; the other guards are facing him.

Now I have to begin in earnest.

I send out lightning to all four Hunters.

It takes a few seconds for them to begin to fall.

The guards are surprised. They can't see me. They maybe even think it's a weird electrical malfunction. But one shouts, 'Raise the alarm.' I blast him too, but with a weaker jolt. I don't want to kill the guards. I let myself become visible and two of the guards come at me but I send lightning to them too. They're stunned and fall but they're not dead. The others are all back against the wall and I hit two of them with more lightning to stun them so that the only people left standing are me and the guard with the clipboard, and he's gripping his clipboard so tight it looks like he's going to twist it in half. He's totally still as if he too is stunned. But then he comes to life and throws the clipboard at me hard. And then other stuff flies at me: pens and handcuffs, mugs and all the stuff that's lying around the room. Of course it doesn't hurt me; it doesn't even land on me, and the guard's Gift isn't that strong. The chairs wobble as if he's trying to move them but they don't lift.

I hold my arms out, saying, 'I won't kill you.' I wait for him to stop. 'Your friends aren't dead. Just stunned.'

A set of keys flies at my face but slides on past.

I tell him again, 'I won't kill you. But I might hurt you if you keep throwing things at me.' And I send a small lightning bolt to his feet to remind him what I can do.

He puts his hands up in defeat. The room goes quiet again. He's shaking.

'What's your name?'

'Sean.'

'OK, Sean. Well, I'm serious about not killing you. If you do as I say, you won't get hurt at all.'

He doesn't reply, but then bends over and is sick. I take his handcuffs and put them on him and push him out and down the corridor to the front door. Through the peephole I see Celia and Gabriel are already in the small holding room.

I tell Sean, 'We've got to let my friends in. I need the password.'

He shakes his head.

'If you don't tell me, I'll kill your friends one by one. You understand that?'

the tower.

Sean is surprisingly cooperative. He only needed to be threatened once before telling me the password and that the keys were on his belt. Celia and Gabriel quickly enter and I tell Celia, 'This is Sean. He's been very helpful.'

Sean says, 'You'll all be killed. Or caught. And then you'll end up in here permanently.'

And then he surprises me by trying to headbutt me, which feels like a soft kiss on the end of my nose and his head is thrown back. That freaks him out and he kicks me, which obviously hurts him a lot and me not at all, though he still can't work it out. I think he might calm down but he just gets madder and it's a waste of time so I hit him and he falls unconscious.

I tell Celia, 'The Hunters are dead but the guards are stunned. I think they'll be waking up soon.' And I show her where they are.

'Find a cell to put them in,' Celia says.

I go along the corridor to the first cell and look in the peephole. Of course it's occupied and when I see inside I begin to think we should kill the guards after all.

The only things in the cell are a thin mattress, blanket, toilet and a prisoner. The prisoner is a woman, very thin and very pale. Her eyes are those of a White Witch. She's wearing bright yellow overalls.

I go along the corridor looking for an empty cell, but each one is occupied and they're all the same: small and bare with a mattress, toilet, blanket, one prisoner in yellow overalls. It's grim. At the last cell the prisoner is sitting but looking at me. He smiles in a strange way when I open the peephole. He's old and thin but I recognize him straight away. I don't even need to say hello, at least not out loud.

I use Mercury's pin to open the cell door and go in and kneel in front of him. He's sitting on the mattress, his back leant against the wall, a blanket wrapped round him. His bare feet are pale, almost blue-white. He's painfully thin, but then he was never fat. He blinks slowly and stares at me. 'Have I gone to heaven, gorgeous boy?'

I shake my head.

'Well, then, this is certainly an unexpectedly pleasant surprise.' Bob's voice is still as strong as ever, which is promising. I only met him once, for a short time, when he helped me on my search for Mercury. I hoped he'd escaped from Soul and the Hunters, but obviously not. Now I'm closer to him I see he's got purple bruises on one side of his neck that seem to stretch down to his shoulder.

'Are you OK?' I ask, and feel stupid because he really isn't.

'Old and tired, and a bit battered. But feeling a lot better for seeing you.' He tries to get up but has little strength and can't manage it.

'Don't try to move. Stay where you are. You're better here for now. I've dealt with the guards.'

'I take it you haven't done all that just to help me.'

'We're attacking the Council building.'

'Jolly good.'

'We need to empty a cell to put the guards in so I'm going to bring another prisoner in here. There'll be some medical help soon. But you have to stay here for now.'

I race back down the corridor and, with Gabriel's help, move the female prisoner from the first cell, along with her mattress and blanket, to Bob's cell. Then we drag all the guards into the first cell. They're heavy, fat. They disgust me. Some of them, including Sean, are waking up. And I just want to get them in and shut the door on them before I get too angry.

I go to the guardroom and look for food, finding some biscuits, a banana and a bottle of water. I take them back to Bob and tell him, 'You'll have to share it with your new cellmate.'

Celia says, 'Time to go, Nathan. We can help the prisoners best by succeeding in our mission.'

Bob looks at Celia and says, 'The Council meeting is happening. The Hunters on the last shift were whinging about the organization of it: there are a lot of Hunters in the building and not enough bathroom facilities apparently.'

I tell Celia, 'Bob's Gift is that he can read minds.'

'Is there anything else you know that might help us?' Celia asks. 'Anything about Soul, Wallend or Jessica?'

'Not much, and nothing good, I'm afraid. The guards are too lowly to have even seen them. They fear them, though. The Hunters respect Jessica,' Bob says, and adds, 'Wallend is a bit of a mystery. They all wonder what he's up to but no one seems to know. He's given the Hunters the power to go invisible, which they like. Now he's developing something called blue. A potion, but I don't know much about it.'

He pauses and then says, 'If you don't mind me asking, are you serious about this attack? There don't seem to be many of you.'

I laugh. 'Reinforcements are coming. But I better get going.'

'There's someone else here who may know more. Though I'm not sure how eager he will be to help.'

'Who?' Celia asks.

'Most prisoners I know from their fear. They spend a lot of time thinking about the past and what they shouldn't say. The guards think about the future. But someone else plans escape, plans revenge, plans a future, plans, plans, plans. Clay's mind is hardly ever at rest. He's on the top floor, I think. It's rather nice to know that the man who caused me to be here is now sharing the same fate.'

And I'm up and out of the door and down the corridor to the internal metal staircase and taking the steps two at a time until I'm at the top. Celia is close behind me, shouting at me to stop, that Clay won't tell me anyway. I keep moving quickly along, checking the cells, trying not to think about the state of the prisoners I see.

Looking through the peephole to the last cell, I find it's as small and grim as all the others, but the prisoner here is sitting in a lotus position and is chained to the wall by both wrists. I can't help but smile.

I tell Celia, 'It's him.'

She replies, 'We don't have time for this.'

I open the door with Mercury's pin. I want him to see me standing over him.

His eyes are different. They still have lots of silver in them, so much that the blue is almost lost, but his right eye is deformed by a mass of scars that run down his face, and as he blinks I see that his eyelid doesn't properly cover his eye. Clay looks at us and says nothing and I keep the silence as long as possible. For fun I take out the Fairborn.

I say to Celia, 'I'm not going to use it, just reminding him that I have it, that I took it from him and that because he lost it he's here in this cell.'

Clay says, 'Celia, what an unexpected surprise.' And he stands now. He does it smoothly and slowly, but I detect a stiffness and although he's still big and muscular he's not looking at all like his old self. He's not tall but wide, and his neck is still big, but it's obvious that he's lost a lot of weight. 'What brings you here ' and for the first time he looks at me as he says 'with that?'

He steps forward, stopping before the chains linking his arms to the wall go tight. And there's an energy to him still.

I say, 'You suit the chains, Clay.'

His eyes are icy, but I can see emotion in there, lots of it. Lots of hate. And I'm not sure if it's all for me. 'Has Jessica been to visit you here? I imagine she likes to see her men in chains.'

He ignores me and turns to Celia, asking, 'Is there any particular reason for your visit?'

I want to ask Clay about Geneva, about how he knew where the apartment was that had the cut through to Mercury's cottage. Did Annalise tell him? Was she working for him? Was she a spy? Did she betray us?

Celia says, 'No. Just checking on you. Time to go, Nathan.' And she starts to swing the door shut.

'I need to know something first.' And I grab the door and hold it open. 'I want some information.'

Clay sneers at me.

'The night we stole the Fairborn from you. I was shot and injured but I made my way back to an apartment. There was a cut on the roof that led through to Mercury's cottage in the Swiss mountains. Do you remember it?'

He stares at me unblinking.

'Do you remember it?' I repeat. 'I got back to the apartment and the place was swarming with Hunters. You drove up. I saw you. I left and then came across Jessica.'

'And cut her pretty face.'

'Nathan,' Celia says, 'we haven't got time for this.'

'You remember the apartment?' I ask.

'I've lost twenty kilos, not my memory,' Clay snaps.

'How did you find it, the apartment?'

He doesn't reply.

'Did Annalise tell you? Was she your spy?'

Clay smiles now. 'Ah, Annalise.' He moves back to the far wall of the cell and slides down it to sit and look at me. 'Where is she now I wonder? Back with her Uncle Soul, some of the guards say.'

'Was she working for you all along?'