‘Dr Fisher?’ Scott says, extending his right hand.

Fisher shakes it, a bewildered expression on his face. ‘Who are you?’ he asks.

‘I’m here to apologise for my wife’s intrusion,’ Scott says, standing on the doorstep, the wind tugging at his overcoat, messing up his hair. ‘Tessa’s been under a lot of strain recently, and I’m sure she regrets coming here to disturb you and your family.’ He casts a puzzled glance in Ben’s direction and then gives me a pointed look, jerking his head in the direction of the road, trying to indicate that I should leave.

I’m so outraged by his patronising words that I almost want to laugh. Almost, but not quite.

‘Yes, well…’ Fisher clears his throat. ‘If you could take her home, I’d be much obliged. I was actually about to call the police. She’s breaking the law coming here, you know. She’s already been warned to stay away from me and my son.’ As the wind whips through the open door once more, Scott and Fisher look at me as though I’m some naughty child who hasn’t done as she’s told.

‘Excuse me,’ Ben says, stepping up to the two of them. ‘But Tessa and I aren’t going anywhere. Not until she gets the answers she came for.’

‘Who are you?’ Scott barks, puffing out his chest.

‘I’m Tessa’s friend. My name’s Ben Moretti.’

‘Oh, right, you’re the chap she works for,’ Scott says dismissively. ‘What are you doing here?’

‘Moral support. You know, Scott, you should be sticking up for Tess, not apologising for her.’

Scott’s face turns scarlet. ‘Who the hell are you to tell me what I should or shouldn’t be doing? I’ve known Tess for a lot longer than you. And she needs help. Professional help. So back off, mate.’

‘Scott,’ I snap, pushing my way forward. ‘If you haven’t come to help me, you should just turn around and go home. When I saw you at the door, I thought you were here for me.’

‘I am here for you. I’m here to make sure you don’t make a fool of yourself and get yourself in even more trouble. I’m not leaving here without you, Tessa. First, you abduct this poor man’s son, then you come to his house and harass him. If you make another spectacle of yourself, the papers will be all over us again, and I can’t put Ellie through that. Not while she’s pregnant. You’re just being selfish.’

‘Selfish!’ I yell. ‘I’m trying to find out the truth. You’re the one being selfish – worrying about your new, cosy little life. Forgetting about me and the children we had together.’

‘I can’t live in the past any more, Tess.’

‘You think I want to?’ I cry.

‘Actually,’ Scott says, ‘yes, I do. I think you’re too scared to move on. And becoming obsessed with this poor man’s son is not helping anyone. Least of all yourself.’

‘Scott,’ Ben interrupts. ‘It wasn’t Tessa who took Harry. Why won’t you believe her?’

‘Because she’s unhinged!’ he yells. ‘I want to believe her, God knows I do, but Tessa has a hard time differentiating between fantasy and reality.’

‘I think you want to believe that,’ Ben says, ‘to ease your conscience. If you tell yourself your wife has lost the plot, then it leaves you free to move on with your own life, guilt-free.’

Scott barges past Fisher into his hallway and squares up to Ben. ‘You need to mind your own bloody business. What’s this got to do with you anyway, Moretti?’

Ben gazes calmly at Scott, but doesn’t reply.

‘Will you all just GET OUT OF MY HOUSE!’ Fisher roars as the gusting wind catches the front door, slamming it shut with an almighty bang.

I almost jump out of my skin.

Silence descends on the hallway.

‘Daddy, why are you shouting? Who are all these people?’

I whip my head round to see Harry leaning over the banister, his gaze sweeping over everyone, eyes wide. Poor boy. He must be wondering what on earth is going on down here. I want to give him a reassuring hug, but Fisher would go ballistic if I approached him.

‘I told you to stay in your room, Harry,’ Fisher says, his breathing ragged. ‘I thought you were watching your Thomas the Tank Engine film.’

‘It’s finished, Daddy. But I can hear that lady upstairs in the attic. She’s making a noise again.’

We all turn our gazes from Harry to Fisher. He opens his mouth, but no words come out.

‘What have you done?’ I say to Fisher. ‘Who’s up there?’

‘Nobody,’ he replies. ‘Nobody’s up there.’

‘Yes there is, Daddy. You said it’s the lady who keeps asking too many questions.’

Fisher looks as though he’s about to deny it once more. But then his expression changes to an indignant frown. ‘She was snooping… Threatening me!’

‘Are you holding her up there against her will?’ Ben asks.

‘No! Well, I was going to let her go…’

Ben and I turn and rush to the staircase.

‘Can you show us where the lady is, Harry?’ Ben asks.

‘She’s in the attic,’ Harry replies. ‘Daddy said she was naughty.’

‘Did he?’ I turn to Fisher and shake my head.

‘What’s going on?’ Scott asks, a bewildered expression on his face.

We ignore him and continue up the staircase.

‘You can’t go up there!’ Fisher cries, making no attempt to stop us. He simply follows on behind, with Scott trailing after him, a strange procession of people led by Harry and me.

Harry takes my hand and pulls me upwards to the landing and then along to another smaller staircase with a door at the top. Dull thuds and muffled cries emanate from beyond the door. I try twisting the brass knob, but it appears to be locked.

‘Key,’ Ben says, turning back to Fisher, holding out his hand.

‘It’s downstairs on my…’

But Ben doesn’t wait for him to finish. Instead, he turns back and boots the door open with the back of his heel. With a splinter of wood, we tumble onto the narrow landing beyond, and I follow the sound of muffled cries through one of the painted wooden doors into an unlit room. I scan the walls until I locate the light switch and press it.

Illuminated beneath the weak ceiling light, Carly sits on a chair, her ankles tied to its legs, arms tied behind her, a gag between her teeth. I turn to glare at Fisher as Ben rushes forward to release her. She blinks, getting used to the light, and then her eyes grow wide with anger as she scowls at Fisher. Carly is not one of my favourite people at the moment, but for Fisher to have tied her up in his attic is outrageous.

I take Harry’s hand and crouch down to his level. ‘Can you go back into your bedroom now, Harry? Your daddy will be down in a minute to see you.’

‘What happened to that lady?’ he whispers in my ear.

‘We were playing hide-and-seek, but now we’ve found her.’

‘Can I play?’ His eyes light up.

‘Maybe later. Go back to your room, okay? Can you do that for me?’

His face falls, but he turns and leaves the room. Good job too, as the language now flying from Carly’s mouth isn’t fit for a five-year-old’s ears.

‘You’re going to jail for this!’ she yells at Fisher.

‘Carly? Is that you?’ Scott says, his face creased in confusion. ‘What are you doing here? What’s going on?’

‘If you’d paid attention to what Tessa had to say in the first place,’ Ben snaps at Scott as he unties Carly’s ankles, ‘maybe you’d have a clue.’

Scott flushes and turns to me for an explanation.

‘Not now, Scott,’ I say, giving him my best withering look. I feel a tug on the back of my coat and turn round to see that Harry has come back into the room. ‘Harry, sweetie, you need to go back to your room, remember?’

‘You’re my real mummy, aren’t you?’ he says in his clear, pure voice, silencing everyone and making me catch my breath.

‘Angela’s been filling your head with nonsense,’ Fisher tells his son, his voice weak, one hand against the wall, the other hand pressed to his chest. ‘Of course this lady isn’t your mummy.’ He reaches out to take Harry’s hand and tries to lead him away, but Harry isn’t budging.

‘My mummy who’s in heaven told me that I had a new mummy who was my real mummy. She said our angel would take me to her. And I think Tessa is my new mummy because she likes trains, same as me.’ He stares up at me, his brown eyes meeting mine, his expression all at once strange and familiar.

I’m sure my heart has stopped beating. I’m sure the world has stopped turning and I’m sure that everyone else has frozen in time. I stare from Harry to Fisher and back to Harry again. I still don’t quite understand what Harry has just said, but I understand that it is possibly momentous. Life-changing.

Everything speeds back up and my heart jump-starts itself. Ka-boom. Ka-boom. A deafening sound that rattles the whole house and makes my vision blur.

‘What’s he talking about?’ Scott asks hesitantly, looking at Fisher, some kind of understanding dawning.

Fisher is quiet, pale, his face twitching, his whole body sagging like a deflating balloon. Everyone turns to him. Even Carly has stopped swearing and is studying the doctor like he’s a rare specimen in a glass case.

‘What’s he talking about?’ Scott asks again. ‘We’re not stupid, Fisher. There’s something going on here.’

If I wasn’t so paralysed with the possibility of what this could mean, I would have a cutting retort for Scott. But now isn’t the time for I told you so.

‘No,’ Fisher says. ‘There’s nothing going on. He’s just a little boy. He has an active imagination.’ But it’s obvious that James Fisher is lying. The bluster and outrage has disappeared from his face. Instead, he now looks scared, shrunken, defeated.

‘You were on duty that night, weren’t you?’ I say to him.

He shakes his head.

‘Scott,’ I say, ‘you must remember. Fisher even changed the records to make out it was Dr Friedland on duty. But Friedland was sick that night, remember?’

Realisation continues to spread across Scott’s face. Finally, he’s listening to me without his usual scepticism.

‘He’s covering something up, Scott. Something bad.’

All the discoveries I’ve been trying to get Scott to pay attention to are finally beginning to sink into his resistant brain.

‘No,’ Fisher says. ‘You’ve got it all wrong.’

In a flurry of movement, Scott pushes past me, grabs Fisher by the neck of his jumper and shoves him up against the wall, his head cracking against the plaster, his glasses falling onto the wooden floor with a thin clatter.

Ben leaves Carly’s side and tries to pull Scott off the doctor. ‘Calm down,’ he tells Scott. ‘Let him go! Let him speak.’

‘What have you done?’ Scott asks Fisher through gritted teeth, hands at his throat, squeezing until the doctor’s face begins to turn purple.

Harry has started to cry, and I swing him up into my arms so he’s facing away from the awful scene in front of me.

‘Stop it! Stop it!’ I yell. ‘You’re scaring Harry! Scott, is that what you want? To traumatise a little boy?’

My words seem to get through, because at last Scott releases his hold on Fisher. The doctor slides to the ground, clutching at his neck and gasping for air. Ben kneels by his side, checking he’s okay.

Harry wriggles in my arms, wanting to be put down. ‘Daddy!’ he cries, twisting out of my grasp and running over to his choking father, throwing his arms around him and burying his face in his chest. ‘Daddy, why are they shouting at you? Why are you shaking?’ His words break down into sobs, and I feel terrible that our arrival here is the cause of this little boy’s distress. But we needed to come: I have to find out the truth.

Fisher begins to sob. He encircles Harry in his arms and kisses the top of his head. ‘All right, I’ll tell you,’ he says, looking up at me and Scott, his voice little more than a whisper. ‘I’ll tell you everything.’