‘Are you nervous, love?’

‘A bit.’

It’s one o’clock on Saturday and we’re in the kitchen, clearing away the remains of the soup I made. I wanted Katie to have something hot inside her before her rehearsal, but she picked at a bread roll and barely touched her soup.

‘I’m nervous too,’ I tell her. I smile, intending to show solidarity, but Katie’s face falls.

‘Don’t you think I can do it?’

‘Oh love, that’s not what I meant.’ I kick myself for yet again saying the wrong thing. ‘I’m not nervous for you; I’m excited. Butterflies, you know.’ I give her a hug, but the doorbell rings and she pulls away.

‘That’ll be Isaac.’

I follow her out to the hall, wiping my hands on a tea towel. They’ve got a technical rehearsal first, then we’re all joining them for the dress rehearsal. I so want to like it. For Katie’s sake. I paste on a smile as Katie disentangles herself from Isaac and he says hello.

‘Thank you for picking her up.’ I mean it. Isaac Gunn isn’t who I’d choose my daughter to go out with – he’s too smarmy, too old for her – but I can’t deny he’s looking after her. She hasn’t once taken the Tube home alone after a rehearsal, and he’s even driving her home after her restaurant shifts.

PC Swift promised to call me the moment they traced Luke Friedland, and the absence of a call has made me jittery. I’ve twice logged on to the website today and looked at the other women listed; downloaded those showing as ‘available at weekends’, and wondered if they’re being followed right now.

Justin comes downstairs. He nods to Isaac. ‘All right, mate? Mum, I’m heading out. I might stop out tonight.’

‘No you’re not. We’re going to see Katie’s play.’

‘I’m not.’ He turns to Katie and Isaac. ‘No offence, guys, but it’s really not my sort of thing.’

Katie laughs. ‘It’s fine.’

‘No it isn’t,’ I say firmly. ‘We are going as a family to watch Katie perform in her first professional play. End of discussion.’

‘Look, there’s really no need to cause an argument,’ Isaac says. ‘If Justin doesn’t want to come, we’re cool with that, aren’t we, Kate?’ He slides a hand round her waist as he speaks, and she looks up at him and nods.

Kate?

I’m standing just a few feet away from my daughter, yet it feels as though there’s a great chasm between us. A few weeks ago it would have been Katie and me against the world; now it’s Katie and Isaac. Kate and Isaac.

‘It’s only a dress rehearsal,’ she says.

‘All the more reason why we should be cheering you on, so you’re ready for opening night.’

Even Justin knows when I won’t be moved.

‘Fine.’

Isaac coughs. ‘We’d better—’

‘We’ll see you there, Mum. You know how to find the theatre?’

‘Yes, yes. Break a leg!’ My smile is making my cheeks ache. I stand at the open door and watch them walk away, waving when Katie turns round. I close the door, the hallway cold from the outside air.

‘She doesn’t care if I’m there or not, you know.’

‘I care.’

Justin leans against the banister. He eyes me thoughtfully. ‘Do you? Or do you just want Katie to think you’re taking her acting seriously?’

I flush. ‘I am taking it seriously.’

Justin puts a foot on the bottom step, bored with the conversation. ‘And the rest of us have to sit through some Shakespeare shite just so you can prove it. Cheers, Mum.’

I’ve arranged for Matt to pick us all up at three. He rings the bell but when I open the door he’s next door, ringing Melissa’s doorbell.

‘I’ll wait in the cab,’ he says.

By the time I’ve chivvied Justin and Simon, and put on my coat, Melissa and Neil are already in the cab. Neil’s sitting in the front, and Melissa’s on the back seat. I slide in next to her, leaving room for Justin. Simon sits on the folding seat behind Matt.

‘Well, isn’t this nice?’ Melissa says. ‘I don’t know when I last went to the theatre.’

‘Lovely.’ I give her a grateful smile. Simon is staring out of the window. I move my foot so it’s nudging his, but he ignores it, shifting his legs away from me.

He didn’t want Matt to pick us up.

‘We can take the Tube,’ he said, when I told him Matt had offered.

‘Don’t be absurd. It’s really kind of him. You’ve got to get over this, Simon.’

‘How would you like it, if the situation were reversed? My ex, driving us around …’

‘I wouldn’t give two hoots.’

‘You can go in the cab, then. I’ll meet you there.’

‘So that everyone else can see how ridiculous you’re being? And know we’ve had a row?’

If there’s one thing Simon hates, it’s people talking about him.

*  *  *

Matt calls over his shoulder to me. ‘Rupert Street, isn’t it?’

‘That’s right. Apparently it’s next to a pub.’

Simon twists round in his seat, the screen on his mobile phone lighting up his face. ‘Waterloo Bridge, past Somerset House and left on to Drury Lane,’ he says.

Matt laughs. ‘On a Saturday? No chance, mate. Vauxhall Bridge, Millbank all the way to Whitehall, and we can take a gamble on the finish when we get to Charing Cross.’

‘It’s ten minutes quicker via Waterloo, according to the satnav.’

‘I don’t need a satnav, mate. It’s all up here.’ He taps the side of his head. Simon’s shoulders tense. When Matt was doing the Knowledge he used to ride around the city on a bike, learning every backstreet, every one-way system. There isn’t a satnav on the market that could get you across the capital more reliably than my ex-husband.

But that isn’t the issue, right now. I glance at Simon, who is looking out of the window; the only sign of his irritation his fingers, drumming on his thigh. ‘I do think Waterloo might be quicker, Matt,’ I say. He looks at me in the rear-view mirror and I hold his gaze, silently asking him to just do this one thing for me; knowing that however much he’d like to score points over Simon, he’d never do anything to upset me.

‘Waterloo it is, then. Then Drury Lane, you say?’

Simon checks his phone again. ‘That’s right. Shout if you need directions.’ His face shows no triumph, or relief, but his fingers cease their drumming, and I see him relax into his seat.

Matt looks at me again and I move my lips in the tiniest of silent thank yous. He shakes his head, and I don’t know if he’s dismissing my thanks or despairing that I felt it necessary. Simon turns to face the rear seat and I feel something against my foot; when I look down, Simon’s is pressed against mine.

Nobody speaks when, fifteen minutes later, we’re in barely moving traffic at Waterloo. I try to think of something to say, but Melissa gets there before me.

‘Have the police got any answers for you yet?’

‘Nothing new.’ I speak quietly, hoping to gloss over it, but Simon leans forward.

‘Answers? About the photographs in the Gazette, you mean?’

I glance at Melissa, who shrugs awkwardly. ‘I thought you’d have told him.’

The inside of the windows has steamed up. I pull my sleeve over my hand and use the cuff to wipe it clear. Outside, the traffic is nose to tail, their lights blurring into streaks of red and white through the rain.

‘Told me what?’

Matt edges forward. He looks at me through the mirror. Even Neil has turned round and is waiting for me to speak.

‘Oh for heaven’s sake. It’s nothing.’

‘It’s not nothing, Zoe,’ Melissa says.

I sigh. ‘Okay, it’s not nothing. The adverts in the Gazette showcase a website called find the one dot com. It’s a sort of dating site.’

‘And you’re on it?’ Matt says, with a horrified laugh.

I keep talking, as much for my own benefit as anyone else’s. Every time I talk about what’s happening, I feel stronger. It’s secrecy that’s dangerous. If everyone knew they were being watched – if everyone knew they were being followed – surely no one would get hurt? ‘The site sells details of women’s commutes to work; which Tube line they take, which carriage they sit in, that sort of thing. The police have linked the site to at least two murders, and to a number of other crimes against women.’ I don’t tell them about Luke Friedman; I don’t want Simon to worry about me any more than he already does.

‘Why didn’t you tell me?’

‘Christ, Zoe!’

‘Mum, are you okay?’

‘Do the police know who’s behind the website?’

I hold my hands up in front of my face, fending off the questions. ‘I’m fine. No, they don’t know.’ I look at Simon. ‘I didn’t tell you because I thought you had enough going on.’ I don’t mention the redundancy – not in front of everyone – but he nods to show me he understands.

‘You should have told me,’ he says quietly.

‘What are the police doing?’ Melissa says again.

‘Apparently the website is practically untraceable. Something about a proxy something or other …’

‘A proxy server,’ Neil says. ‘Makes sense. He’s logging on via someone else’s server, to avoid detection. I’d be surprised if the police have any joy there. Sorry, that’s probably not the answer you want.’

It isn’t, but it’s the answer I’m starting to get used to. I look through the window as we cross Waterloo Bridge, and let the others talk about the website as though I’m not there. They ask the questions I’ve already asked the police; go round the same circles I’ve already travelled. My fears are unpacked and examined; analysed for entertainment like an EastEnders plotline.

‘How do you think they get the details of people’s commutes in the first place?’

‘Follow them, I suppose.’

‘They can’t follow everyone, though, can they?’

‘Can we change the subject now?’ I say, and everyone falls silent. Simon looks at me, making sure I’m okay, and I give a little nod. Justin is staring straight ahead, but his fists are clenched on his knees and I kick myself for talking about the website in such a flippant way. I should have sat the kids down privately and explained what was going on; given them a chance to tell me how they felt. I reach out a hand towards Justin, but he stiffens and angles his shoulders away from me. I’ll have to find a quiet moment to talk to him later, after the play. Outside there are people walking in pairs and on their own, holding umbrellas and tugging hoods over windswept hair. No one is looking behind them; no one is checking to see who’s watching them, so I do it for them.

How many of you are being followed?

Would you even know?

Rupert Street theatre doesn’t look like a theatre from the outside. The neighbouring pub is noisy and full of young people, and the theatre itself has no windows on to the street. The brickwork is painted black and a single poster on the door gives the dates of Twelfth Night.

‘Katherine Walker!’ Melissa squeals, pointing at the tiny writing towards the bottom of the poster.

‘Our Katie, a proper actress.’ Matt grins. I think for a second he’s about to put his arm around me, and I take a step to the side. Instead he gives me an awkward punch to my shoulder, like he’s greeting another cabbie.

‘She’s done all right, hasn’t she?’ I say. Because although she isn’t being paid, and although the Rupert Street theatre is really just an old warehouse with block staging and rows of plastic seats, Katie is doing exactly what she always dreamed of. I envy her. Not for her youth, or her looks – the way people assume mothers envy their daughters – but for her passion. I try to think what I might have done; what grand passion I might have followed.

‘Did I have a passion when I was her age?’ I say to Matt, quietly enough for no one else to hear.

‘What?’ We’re trooping downstairs, but I need to know. I feel my identity slipping away from me, reduced to a commute on a website for someone to buy. I pull Matt’s arm, making him fall behind the others, and we stand in the shadowed curve of the staircase while I try to explain.

‘Something like Katie’s acting. She’s so alive when she talks about it; so driven. Was there something like that for me?’

He shrugs, not sure what I mean; why it’s suddenly so important. ‘You liked going to the cinema. We saw so many films when you were pregnant with Jus.’

‘I don’t mean like that – that’s barely even a hobby.’ I’m convinced I’ve simply forgotten; that somewhere, buried inside me, is a passion that defines me. ‘Remember how you were mad for motocross? You’d spend all weekend at the track, or fixing up bikes. You loved it so much. Didn’t I have something like that; something I loved more than anything else?’

Matt comes closer, the smell of cigarettes and extra-strong mints reassuringly familiar. ‘Me,’ he says quietly. ‘You loved me.’

‘Are you two coming?’ Melissa runs up the stairs, then stops, one hand on the railing. She eyes us curiously.

‘Sorry,’ Matt says. ‘We were just taking a trip down memory lane. It won’t surprise you to know that our Katie has always loved the limelight.’ They walk on down the stairs, Matt recounting how five-year-old Katie once took to the stage on our Haven holiday, to sing ‘Somewhere over the Rainbow’. I follow behind them, letting my heart rate slowly return to normal.

Downstairs, Isaac makes a big fuss of showing us to our seats. We’re surrounded by seventeen-year-olds clutching well-thumbed copies of the play, coloured post-it notes protruding from the pages.

‘We always send out invitations to the local schools when we need an audience for a dress rehearsal,’ Isaac says, seeing me looking around. ‘It helps the actors to have a proper audience, and Twelfth Night’s always on the syllabus somewhere.’

‘What kept you?’ Simon says, when I slide into my seat beside him.

‘I was looking for the loo.’

Simon points to the door to the side of the auditorium, clearly marked Toilet.

‘I’ll go later. They’re about to start.’ I’m aware of Matt sitting down next to me, radiating warmth I can feel even without touching him. I lean towards Simon, my hand in his. ‘What if I don’t understand it?’ I whisper. ‘I didn’t do Shakespeare in school – all that stuff you and Katie were talking about, I don’t have the first clue about it.’

He squeezes my hand. ‘Just enjoy it. Katie’s not going to ask you about themes; she just wants to know you thought she was brilliant.’

That’s easy. I know she will be. I’m about to say as much to Simon, when the lights dip and there’s a hush across the audience. The curtain opens.

If music be the food of love, play on.

There’s only one man on stage. I had imagined Elizabethan ruffs and frilly cuffs, but he’s dressed in skinny black jeans and a grey T-shirt, his feet in red-and-white Converse. I let his words fall around me like music; not understanding every line, but enjoying the sound they make. When Katie comes on, accompanied by two sailors, I almost call out in excitement. She looks sensational, her hair twisted into an elaborate plait that hangs over one shoulder, and a tight silver top. Her skirt is ripped, a consequence of the shipwreck conveyed to us a moment ago through flashing lights and crashing sound effects.

My brother he is in Elysium. Perchance he is not drowned: what think you, sailors?

I have to remind myself it’s Katie up there. She doesn’t miss a beat, her presence filling the auditorium even when she isn’t speaking. I mean to watch her, and her alone, but I’m swept away by the story; by the other actors, who throw words at each other as though they’re sparring – the winner the one who has the final say. I surprise myself by laughing, then being moved to tears.

Make me a willow cabin at your gate. Her voice carries across the silent audience and I realise I’m holding my breath. I’ve seen Katie in school plays, practising audition pieces, singing in holiday camp talent competitions. But this is different. She is breathtaking.

Oh, you should not rest

Between the elements of air and earth,

But you should pity me.

I squeeze Simon’s hand, and look to my left, where Matt is grinning fit to burst. I wonder if he sees her as I do. Practically an adult, I often say, when I’m telling people about Katie, but now I realise there’s no practically about it. She’s a grown woman. Whether she makes the right decisions in life or the wrong ones, they’re her choices to make.

We clap wildly when Isaac takes to the stage to tell us ‘This is where the interval will be’, laugh in all the right places, and sit in sympathetic silence when the lighting guy messes up his cues and plunges Olivia and Sebastian into darkness. By the final curtain call I’m dying to jump out of my seat and find Katie. I wonder whether Isaac will take us backstage, but Katie runs on to the stage and hops down into the audience with us. We crowd round her, and even Justin tells her it was ‘all right’.

‘You were amazing …’ I realise I have tears in my eyes, and I blink them away, laughing and crying at the same time. I hold both her hands. ‘You were amazing!’ I say again. She hugs me and I smell grease paint and powder.

‘No secretarial course?’ she says. She’s playing with me, but I drop her hands and instead cup my palms around her chin. Her eyes are glittering and she’s never looked so beautiful. I rub a smudge of make-up away with one thumb.

‘Not if it isn’t what you want to do.’

I register the surprise on her face, but now isn’t the time to talk. I step aside and give the others a chance to tell her how brilliant she was, basking in her reflected glory. From the corner of my eye I see Isaac watching her. He catches my eye and walks over.

‘Wasn’t she brilliant?’ I say.

Isaac nods slowly, and as if she can feel his eyes on her, Katie looks up and smiles.

‘The star of the show,’ he says.