I reach towards the dome but hesitate and turn to look at Wallend. He's staring at me, alert now, and I have second thoughts about touching the glass. I walk round the dome. It's about three metres in diameter and seems perfectly shaped and clear, like an upturned glass bowl. But the more I look at it the more I'm sure it's not simply glass. The pyramid of bottles inside is neatly perfectly arranged, except for a few gaps, as if some bottles are missing. As I continue to walk round, I spot a few more gaps. Or am I mistaken? One that I thought was missing is there now.

And then I get it. The bottles become invisible as the Hunters they are connected to become invisible. I watch for a moment and see two vanish and one reappear.

I walk back to Wallend. 'Open the dome. I want to look at the bottles.'

He shakes his head.

I lean forward and hiss at him, 'Open it or I cut off your ear.'

'I can't.'

'I think you can.'

I grab hold of his ear and pull it hard, saying, 'Last chance or this is going.'

He hits out at me now with his arms and then kicks me. I hit him back, let him fall to the floor and take the scalpel and slice his ear off, even though I know it will not help me one bit. But he has to know that I'll follow through with what I say.

He screams once and clutches at his bleeding head.

I throw the ear at the dome.

Electricity sparks fly around the piece of flesh and it bounces back to land on the floor near Wallend. The dome crackled a blue-white colour but only briefly and only in the area where the ear hit it.

I look at the scalpel in my hand and wonder if I should try that.

Why not?

The scalpel hits the dome and for a second seems to fuse with it as the dome changes colour around the point of impact. Then the scalpel flies back towards me, landing with a tinkle on the ground.

I make another circuit of the dome, but this time looking at the other equipment in the room. There's a bench along the wall opposite the door we came through, and there are many things on it: paperwork, surgical equipment, pens, computer, but nothing to indicate how to open the dome.

I say to Wallend, 'You must add to the pile of bottles in there. When there are new recruits you want to give the Gift of invisibility. So how do you do it?'

He shrinks lower and I notice the scalpel has disappeared from view.

'And is there a spell that manages the invisibility or does this just give the Hunter whose bottle is in there that Gift?'

He doesn't answer. His ear isn't bleeding as much as I thought it would. Maybe he can heal reasonably well after all. His hands don't look too bad now either.

'If you're not going to talk to me, Wallend, then there isn't much point in you having a tongue.'

But I don't want to do any more surgery on him; it's disgusting. 'Do you use this to open it up?' I ask, picking up a laptop and weighing it in my hand. 'I've never been great at computers but I'll try it.'

Wallend cowers but doesn't try to stop me, so I suspect it holds nothing important and I toss the computer at the dome. Again at the impact zone the dome turns blue-white and the laptop is held there for a second, as if caught, before it is rejected and thrown out. There are sparks and a lot of crackling but after a few seconds the dome is back to its quiet, clear norm. And Wallend has taken those few seconds to move round to me, scalpel in his bloodied paw. He must know he doesn't stand a chance.

I step towards him and realize as I do that that's what he wants. His only hope of beating me is to push me into the dome. And I have to admit I'm rather curious myself what would happen.

Wallend charges at me but he's slow and weak and I sidestep him, and although he grabs me I push him off and use his momentum to force him towards the dome.

He clings to me then.

'Really?' I ask him. 'You want to fry or should I just hold your face against the dome and see what happens?'

'No!' he whimpers. And at least now he seems to know that I'll do it. 'Please. I'll open it. There's a spell. I need the wand.'

'The wand?' I've never heard of anyone actually using a wand.

'That. On the bench over there.'

I drag him with me to where he indicates.

It's a stick. Admittedly it's a nice stick with the bark peeled off and it looks worn and smooth. I pick it up and wonder if I'll feel something, something alive the way the Fairborn feels. But I get nothing.

'How does it work?'

'With the correct words. And the wand.'

And now I'm stuck. Do I let him tell me the words or do I let him do it himself? The amulet should protect me either way. I hold the wand out to him and say, 'Take it and open the dome. You've got one chance to get it right.'

He nods and the tip of his tongue appears and licks his top lip. He takes the wand in his right hand, grasping it between his fingers. He doesn't show any pain or difficulty in doing that. I think he's healed fine.

Instead of touching the dome itself, he touches the point of the wand to the channel it sits in and says, 'Dome, liquefy.'

The dome becomes opaque white instantly, and the top changes to be like liquid, like milk, and it flows to the floor and into the channel so that it's brimming and looks like a glistening, shining pool. The bottles are two strides away, waiting for me to destroy them.

'Bring me a bottle,' I say.

Wallend hesitates and then steps over the channel of milky liquid, reaches slowly up and picks up the topmost bottle from the pile between his two paws. He looks strong and unwavering now, but then goes back to being bent over as he brings the bottle to me. The bottle is plugged with a cork, and tied to the cork is a small label that has a name on it. The Hunter's name, I guess. Inside is a piece of tattooed flesh. I take the bottle and smash it on to the bench. Nothing happens.

It seems that the dome is a way to secure and protect the bottles. Some of the bottles are still invisible but I think that if I break the bottles then the Hunters will lose the ability to go invisible. Only one way to find out. I snatch the wand from Wallend so he can't do anything to the dome and I go to the pyramid and feel for one of the missing bottles near the top of the pile. It's there but invisible. I pull it out and drop it to the floor. The broken glass appears with the flesh and the cork and the label. So, breaking the bottles does break the spell. It's as simple as that. All I've got to do is break all the bottles and Soul's army will lose the ability to go invisible. I swipe at the top of the pyramid, knocking a few bottles, and as they crash down Wallend shouts, 'Dome, solidify.' I turn and see he's standing, looking strong, and the milky-white wall rises in front of me and I turn and try to move through the liquid except I can't. The dome is already completely white and solid. And then it clears and Wallend stands on the other side, grinning at me victoriously.

I've still got the wand and I hold it up to him.

'It's a stick,' he says. 'I was trying to enchant it, but couldn't get it to work. It's just a stick.'

I touch the stick to the base of the dome and say with as much emotion as I can muster, which is a lot, 'Dome, liquefy.'

Nothing happens except perhaps that Wallend's grin widens.

He says, 'The dome recognizes two masters only. Me and Soul. It won't do what you say.'

I pick up two bottles and throw them at the dome. It reacts the same way as when something hit its outer surface, becoming opaque for a second or two and then becoming clear again.

'I'll destroy all the bottles,' I say.

'Then the Hunters will lose their ability to turn invisible but they'll still be Hunters. And you will still be my prisoner.'

Well, I'd rather the Alliance fought a visible army so I lash out at the bottles, kicking them at the dome. There's glass flying all around me but the dome doesn't show any hint of a weakness.

Eventually I'm done; there are no more bottles to smash. I'm panting with rage and frustration, standing on crushed glass and bits of flesh as the dome returns to its clear smoothness. And Wallend is still there grinning at me. I thought he might take the opportunity to run and get help but he's not in a rush. He's confident I'm not going anywhere.

He sits on a chair and looks at me. 'You've made a mess of your new home.' He smiles. 'Soul would like to see you here. He was expecting you but I'm tempted to not tell him you've arrived until after you run out of air. It'll be a few hours, I think. You lived a long time in a cage and now you're going to spend the rest of your days, or should I say hours, in this one.'

I swear at him.

'Soul thinks we can use you, have you work for us, but ' he holds up his hands 'I know you for what you are: an evil Black Witch, just like your father.'

'You want to see evil? I've not even started.' And I take the Fairborn and leap at the dome with all my strength. Where the knife hits the dome it becomes opaque for a second and then it throws me back so I land among the glass shards, which shatter beneath me but feel like a feather bed. I get up and raise the Fairborn again.

Wallend comes closer now, studying me. I think he's noticed that I'm not cut by the glass.

I move to stand opposite him and stab the Fairborn at the dome. It bounces my arm back again.

He says, 'You're wasting your time. You can't break out. It's impossible. The magic is too strong.'

Now I grin at him and I say, 'Want a bet?

I try being gentler this time. Slowly putting the tip of the knife to the dome and pushing it down, still using all my strength. I'm thrust back again but not as forcefully.

There's no mark on the dome. It turns opaque briefly and then returns to its clear self. But I can feel the Fairborn in my hand and its desire to cut, to rip the dome. To the Fairborn, the dome is alive, and the Fairborn doesn't like alive.

I repeat the same slow cut and the same thing happens, but I still sense the Fairborn's desire, its fury. It's madder than I am. I make the same cut again, and the dome doesn't throw me back this time, and I see there's a small opaque line that stays longer than last time, and when it disappears there's a fine scratch in the surface of the dome. A weakness. The Fairborn seems to sense it too, and it wants more, wants to go deeper.

I repeat the cut, slowly and forcefully, pushing the Fairborn into the dome and pulling it down. I'm thrown back, almost to the other side of the dome, but this time the opaque colour takes longer to clear and the scratch left behind is deeper and longer than before. I stab once more and, with the weight of my body behind it, the Fairborn's tip is embedded in the dome. I lever the knife up and down, my arms shaking, my whole body shaking. The dome has become opaque and white and I lever faster and push harder, and sweat blooms out of me but I keep levering. And then the dome cracks from floor to floor, right over its peak, and is opaque all along that crooked line. I lever the Fairborn from side to side now and the dome cracks again, crossing the first. Then I take the Fairborn out and thrust it hard at the point where the two cracks meet and I kick high at the place where the blade first went in, and a hole appears in the dome and through it I see Wallend already at the door. Leaving.

I send out lightning. Wallend falls, stunned not dead. I kick at the dome to make a hole big enough to get through. By the time I'm out, Wallend is groaning and trying to crawl.

Kill or capture are the options now, so I go to Wallend and let the Fairborn choose.

blue.

Wallend is dead and I've destroyed all the bottles that were in the dome. No one has come to investigate the noise; the doors are thick and we're at the top of the building, away from everyone else.

I go invisible as I leave Wallend's office, and the corridor is as silent and empty as before.

Now for Soul.

I make my way towards the ground floor and the main Council Chamber where I used to have my Assessments. Behind that is a series of private offices and small meeting rooms. Soul's office is there; I have to hope that he is too. From what Wallend said, Soul knows I'm coming and the Hunters must be here to protect against an attack.

I've come down the main staircase now and I stop in the foyer. The Hunters are still here. I see Gabriel. He's perfect in his disguise as a brutish Hunter. I watch him for a few seconds. He holds his head up and looks around but not at me.

I head to the Council Chamber and am soon in a series of corridors like the ones I remember from my Assessment days with stone walls and stone floors and many doors off to left and right. I stand tight against the wall as two Hunters patrol past, then turn left, then first right, and here is the corridor and the bench where I used to sit and wait with Gran.

It seems strange to see it now. I sat there every year, humiliated and afraid. The last time I was here, I sat there cuffed and Annalise came through the far door with her father. That must have been one of the days she was brought in for questioning. I'm sure it wasn't an accident, that they came this way and reminded her that I was still alive and a danger to society. Or was it all a set-up? Was she a spy even then?

Now everything feels different. There's a Hunter near me and another one at the far end of the corridor. Two women come out of the Council Chamber, smiling, and sit on the bench, my bench. The women are talking about their children.

The door to the Council Chamber is open and, just like at my Assessments, a guard is standing inside the door. I move into the room and still it manages to make me feel small as it always did, although the room is laid out differently to when I've been here before. The large table is where it always was, but adjoined to it are three other tables, making a sort of square. Most of the seats are empty, including the three that look like thrones, the three that were occupied for all my Assessments and which I now am sure will be occupied by Soul and Jessica and possibly Wallend, though of course he won't be coming.

I need to get on. Soul isn't here and I need to find him, preferably in a place a bit more private than this.

As I make my way back to the door, I see a man I recognise. I've only seen him once before, only for a few seconds, but the memory is clear in my mind. Annalise's father. He looks older and much more tired than when I last saw him. Is that how you look when your daughter is a prisoner or a spy? Or maybe it's how you look when two of your sons are dead. I'm not sure what I want to do about him, but I can't do anything at the moment. I've got to find Soul.

Back in the corridor, the women are still talking. One says, 'I heard he's going to demonstrate the blue.'

The other woman lowers her voice and replies, 'Yes, but on whom?'

I turn right down the corridor, to the door at the far end. I can't risk opening it with a Hunter right there. I have to wait for someone to come out and it's a few minutes before that happens. But then the door opens and I manage to slide through without touching anyone.

I walk fast now, round the corner, right and right again, to Soul's private office, and it's all exactly as in the mock-up. There's a guard at this end of the corridor and another outside the door.

I've prepared for these guards, just as Celia told me to. The guards look bored but they also look to be the biggest men I've ever seen. Still, I'm invisible and invincible. I walk slowly and silently past the first, take hold of the doorknob and turn it slowly. The nearest guard might not notice the knob turning but he will notice the door moving. I open it and slide through, leaving the door ajar.

And now I face my enemy.

He's sitting behind his desk, pen in hand. He looks up at the door and it seems as if he's looking at me. The desk, a huge mahogany thing, has some papers on it and also a large glass bowl containing a turquoise blue liquid, and over the top of the bowl is a sheet of glass.

Soul frowns. The guard appears in the doorway behind me.

'Yes?' Soul asks. 'Did you want something?'

'No, sir. I ... I didn't open the door.'

Soul shouts, 'Get reinforcements!' But I'm already letting the Fairborn thrust itself into the guard's neck. Soul stands, whipping the glass sheet off the bowl and throwing it at me. It slices sharply through the air, and I send a blast of lightning that hits the glass sheet and another that hits Soul. The other guard appears in the doorway and I blast him with lightning too.

It's silent and still again. Shattered glass is strewn across the room, smoke coming from the jacket of the second guard.

I wait a few seconds, expecting someone to come running, but nothing happens except that Soul rolls on the floor by his desk and groans. I walk over and check he hasn't got a gun. I know he can't hurt me with it but I don't want any more sound.

The first guard fell sideways into the room but I have to drag the second in and out of sight from the corridor. It's ridiculously difficult because he's the weight of a small buffalo. I'm using all my strength and can barely budge him, but slowly and with a lot of effort I get him far enough into the office so that I can shut the door.

Soul is stirring. The man who has killed so many, ruined so many lives, tortured so many of his own people, as well as many Black Witches and Half Bloods and me, is at my feet. The Fairborn in my hand is slavering at the sense of blood close by.

Soul doesn't move but I see his eyes open just a little. It's a movement I recognize. The movement of someone used to being careful, to being watched, wanting to know who is watching him, someone whose brain is working hard, on full alert, when it looks like it's only half awake.

I nudge him with the toe of my boot and then feel annoyed with myself for being weak and soft with him and kick him hard.

He doesn't grimace and I think he must be healing straight away as he turns his face to look at me. Yes, he's healing; I can see a look in his eyes, that thrill, his eyes sparkling brightly for a split second.

'Nathan! What a lovely surprise.'

'Is it?'