aWhere do we start? What are we looking for?a I ask.

aHere,a says Sophia, moving towards an old green filing cabinet, standing by itself and looking out of place in this smooth new office s.p.a.ce. aIave seen him lock it after heas put things in it. We might find his address book or diary.a aAre you sure?a I open a long rolling cupboard door to reveal ranks of white filing cabinets, all unlocked.

aYup,a she says, opening a desk drawer. aItas just that we need the key.a aOr a screwdriver a" thatas what they always useaa I say. Sophia glances up at me. aWell, they do. Even Dad uses one when he canat open things.a I find a pair of large scissors in a box underneath the desk and try slipping the blade into the lock. It doesnat work a" itas obviously the wrong thing to use.

aBingo,a says Sophia, holding up a tiny key.

But weave bent the lock, so even with the key it takes ages to get the drawer to open.

And when it does, I donat understand what weave found.

aWhat are these?a I ask, flicking through ledgers filled with hundreds of tightly written numbers.

Sophia shrugs. aOr these?a she says, pointing at a collection of flash-drives and camera storage discs. aWe should take them,a she decides.

aWe need to copy them,a I say.

She stares at me.

aOtherwise itas inadmissable evidence.a She still stares at me.

aIf you take them, you canat prove they came from here, but if you copy them, then they wonat even know youave seen them. If it ever comes to a police investigation, then the police have to find them here otherwise they canat use them as evidence.a aLet me guess. You know that because itas in something like The History of the Swollen Shrew? Or Dark Days in Kansas?a aNo. This time I heard it on the radio.a I smile.

aOK, I get it,a says Sophia. She reaches into another drawer and pulls out a brand new, unopened flash drive. aThey always have stacks of these.a She switches on the white computer, and copies the disc files from the individual chips to the new flash drive, while I begin to scan the ledger into the photocopier.

aWhat about his diary a" should I be looking for it?a I ask.

aIall check his engagements on this.a She starts to click through Pinheadas emails on the computer.

Iam so intent on the photocopying, I donat see what Sophiaas doing, and donat look up until I hear her make a little choking sound.

aWhat is it?a I ask.

aNothing a" we have to go.a The screen on the computer fades into black.

I scoop the copied pages from the printer, and turn the ledger over to get the last few entries.

aIam done,a she says. aDo you want to do the lift thing? Or shall I?a aNearly finished,a I say. aWe could do it together.a We pick up every sc.r.a.p of tinfoil, I stuff the photocopied diaries into Nedas bag, and we try to put the filing cabinet lock in the right position.

aRight,a says Sophia, putting the key on the window sill. aTime to get out of here.a But we donat have time, because the lift pings. We stare at each other. Sophia pushes the office door shut and runs for the big white cupboard of filing cabinets. I stuff the cardboard guns into the broom cupboard and dive for cover under the kneehole of the huge desk that is too small and too public.

I hear the peeping of the keypad outside. The door handle clunks and someone comes in. I draw my knees into my chest and barely breathe.

aSo do you think it was them?a Itas Wessonas voice.

aBound to be.a Someone tries the drawer of the green filing cabinet. I hold my breath but it stays closed. aHavenat got in here, though, have they, so whatas she playing at?a A manas voice. Pinhead.

Something sounds like itas being dragged across the carpet. I really hope we havenat left anything out there.

Knees appear right by my head. Pinstripe-suited ones. Then very close by, I hear the high-pitched beeps of someone putting numbers into a phone. Pinhead starts talking.

aYeah, itas me. Yes, weare on the trail. The security boys downstairs rang me.a Silence while he listens for a bit. aYeah, Sophia, and the other girl a" theyare somewhere in the building.a He listens. aLook,a his voice softens, like heas just flipped the charm switch. aDonat worry a" they wonat be able to stop us, weare nearly there.a More silence. aYeah, yeah a" Iave got it covered a" there wonat be any loose ends. You know me, I never leave loose ends.a If I had to run, I couldnat. My footas fallen asleep.

Thereas a sound of sticky tape coming off a dispenser.

aLook a" itas fine a" itas all safe, no one knows anything a" no one even knows about this phone. Thereas nothing leading from me to you, nothing leading from the warehouse to me. No one knows anything. It all looks kosher.a A pause. And I think about how different he sounds. Not at all like the man that was charming Miss Sackb.u.t.t in our kitchen.

aYeah a" yeah. Anyway, itas just a blip, theyare just children, tiny schmucky children. Donat worry about it. Iall take care of them a" no problem.a The phone clunks on to the desk above my head. I look up instinctively, and to my amazement see a huge bundle of cash taped to the underneath of the desk. I draw myself away from it.

aWhat did Jim say?a asks Wesson.

aWants to keep his nose clean a" worried about his public reputation.a A different phone beeps. A call in or out? aYeah? No, I donat actually know.a Pinheadas voice is different, more irritated than in the last call. aYes a" yes a" donat worry, Iall find her.a Fingers drum on the desk above my head. aNo a" I said I would, OK? Yes, I lost her but Iall find her. Donat panic and donat ha.s.sle me a" Iam doing my best OK?a The phone clunks back on to the desk.

aAnd?a says Wesson.

Pinheadas talking: aSheas antsy, sheas worried about her little darling a" but itall be all right. OK, letas find those kids, and this time, if I catch that toe-rag Sophia a" I swear Iall kill her.a His hand reaches under the top of the desk, towards the money.

I pull back. Instead of taking the cash, the hand holds a mobile phone under the counter top. With his other hand, he presses sticky tape to either side until the phone is stuck fast to the underside of the desk.

aRight a" time for me to get out of here. You all right staying here, darling? Keep a look out and give me a ring if anything happens. Iall go and search the rest of the place.a aOf course, Trevor, love. Take care.a Then thereas the long sticky sound of kissing.

Pins and needles are worse the longer you leave them.

When Wesson helps herself from the water cooler, I risk moving my dead leg. Itas excruciating. Absolutely agonising. It feels as if someoneas pulling it off my body and itas all I can do to stop myself from screaming.

I think of Irene flying those aeroplanes, stuck in the same position for hours in a freezing c.o.c.kpit. If she could do it, so can I.

Mind you, she didnat have Pinhead after her. Racehorse trainer, bouncer, boxer, sausage maker, international criminal. Gangster. Spy. Murderer.

All the stories of concrete overcoats and missing relatives become horribly possible. I keep playing the conversation over in my mind. No loose ends. No loose ends. Am I a loose end?

And who was the second caller a" was it my mum? Or Miss Sackb.u.t.t? Maybe Sophiaas mum a" though it sounds like sheas already propping up a motorway in j.a.pan.

Away to my left in the cupboard of filing cabinets, Sophia has managed to stay completely silent, but Iam wondering how long I can stand this for.

Are we going to have to wait for Wesson to give up and go home?

I watch the sun cross from one side of the room to the other, the lights come on in the office, and finally, I listen to the sound of Miss Wesson bedding down on the floor, her head scarily close to my ankle on the other side of the backboard of the desk.

For some time Wessonas breathingas fast, too fast to be asleep, and then it turns from fast to slow, and I wonder whether I could sneak out past her nose, but Iam not at all sure I could walk well enough.

De dee dee, da dee dee, da da dee dee dee.

A mobile phone rings and I use the noise to shuffle my legs while Wesson gropes to switch it on.

aYeah?a she says.

Silence.

aOh.a Silence.

aWell, youave got the car but I could get a cab, meet you there.a Silence.

aSee you in half an hour and, Trevor, love you.a The carpet crunches as Wesson stands up and fabric rustles. She pulls on some sort of clothing, and then thereas an empty silence as the door clicks shut.

I sit motionless, waiting.

Ping.

The lift doors clunk.

The whole office floor feels wrapped in cottonwool silence. I risk pushing my leg out of the side of the desk. No one leaps on me, no one shouts, although everything aches.

I stand, my legs shaking and pull back the door on the filing cabinets.

aLottie?a At first I canat see her, then I realise sheas crammed herself into the gap along the top but so far back that only her eyes give her away.

aSheas gone,a I say, reaching my hand out to pull Sophia from the s.p.a.ce.

It takes a few minutes to get her out, and like me, sheas seized up.

aDid you get that?a I say. aThe conversations?a Sophia nods. She gazes at me, wide eyed. aSee a" I said he was scary.a I wipe a homesick tear away from my eye. Iad really like to go home now. I want it all to stop. But instead I say, aThereas a bundle of money under here. And a mobile phone.a Sophia drops to her knees and peers under the desk.

aThereas loads. Hundreds. What did he mean, Sophia a" about the loose ends?a I say, swallowing the tears, trying to sound sensible.

She pulls out the bundle. Itas a thick wad of twenties wrapped with a paper band and a bank stamp. aI donat know, Lottie.a She shivers. aDo you think it would be wrong to take this?a I stare at the bundle, and think of the conversation we just heard.

aNo, I donat. Take the phone, too, and letas get out of here.a Itas easier to think about leaving the office than to leave it.

aTheyall find us in seconds if we use the lift, weall have to go by the stairs,a I say.

aDo you think theyare still looking for us?a Sophia says, pulling open the heavy fire door.

aI do. They never saw us leave. They must still think we might be here,a I say. aUp or down?a aWhy up?a she says.

aTheyall expect us to come out of the bottom, so perhaps we should try the top.a We start climbing the stairs. I lose count after six floors, in fact I canat even work out which way Iam facing. I realise that Iam much more at home in the countryside, where I can see the sky. Here, without the sun, thereas nothing to tell you where anything is.

Iam boiling within seconds, and out of breath within minutes.

aDo you think Ned told them we were coming here?a she asks.

I walk up another flight of steps. Would he or wouldnat he?

An improbable thought comes to me. aI suppose he might have been worried about us?a As I say it I feel something curious, thatas not just to do with being out of breath. A kind of warm, sweet sadness, that comes with the thought of my brother actually caring about me.

I push it to one side and make myself walk up another flight of steps. Sophia skips up the last few steps and I rush to follow.

A minute later and Iam regretting it. These buildings are seriously tall. So tall that you can hear them blowing in the wind, and the tops are not nearly as smart as the entrances would make you think.

I would rather stamp up the staircase forever than be stuck here on top for one minute.

We step out into a howling gale. Rain beats on the roof all around us and itas freezing. I stop in the doorway, letting my eyes sort the shapes in the dark. Tall chimneys thrust up into the rain cloud, aerials, pipes, all standing dark against the yellow nightglow of the city. Things I canat see scrunch under my trainers. Gravel? Seagull bones? Eggs? Poo?

Sophia picks her way through the shafts and pipes to the side of the roof. I can see her clearly now; itas not at all dark really. A steel parapet runs around the side, with one small gap.

aThe fire escape?a she shouts.

I lean against the wind. I can barely walk on the flat so how on earth am I supposed to go down a fire escape? This was mad a" I should never have suggested it.

Sophia leans on the parapet, looking down. aItas not too bad,a she says. aA ladder for a couple of storeys then a proper staircase.a aReally?a I say, as my ladder dream comes back. I canat move.

aIf you donat look down, Lottie, you ought to be able to climb it.a Sophia stands, her feet already below roof level, and beckons to me.

This is not good. This is exactly the kind of thing that stopped me from wanting to go to Bream Lodge and theyave got a safety net there.

I walk towards her, keeping my eyes on her eyes and avoiding the huge falling landscape view behind her.

aTurn around, Lottie.a I turn.

aGet on your hands and knees.a I drop to the ground. Fragments of concrete and roofing felt dig into my palms. This could be the last time I ever look at anything close up. A tiny snail clings to the side of the parapet. How did he get all the way up here?

aNow put your feet down on to the first rung.a I stretch my leg down, feel the step in the arch of my foot, and pull the other leg down, too. Iam shaking. My whole body is shaking. I am not designed to do this.

aPut one hand on either side.a I grip the black handrail. Itas rough, badly painted, slightly rusty a" exactly like the ones in my dreams although this one seems quite solid.

The roof, the last solid thing, disappears upwards in front of my nose.

One step, two step, three step, pause.

The ladder just goes down and down.

One step, two step, three step, pause.

One step, two step, three step, pause.

Sophia talks to me the whole way, calling encouragement.

aNearly there, Lottie!a she shouts. aYouare doing so well.a Iam doing well. Yes, I have to remember that; Iam getting there, even with the gale whipping around my head and Nedas backpack pulling me towards the ground.

Ned. If he were here head be doing this; head even be enjoying it.

I wonder what happened when we left him. Iave never even considered what he might have felt as I jumped out of that window or that he might actually have enjoyed the adventure. He would have loved this. A pang of guilt flashes in my brain and for a moment Iam almost not scared, just conscience-stricken.

I stop, and look down. Between me and where I think the ground is, I can see a criss-cross of bars; they might be close, they might be miles away, but they move over the lights below when I move my head.

Moving my head. Not a good idea. I go back to staring at the wall in front of me and put my foot down again.

I must do this. Irene walked across Scotland. Flew aeroplanes on her own. Worked as a doctor in war zones. She was real, not just a character in a book. She really did it.